Juicy Tri-Tip Steak with Creamy Mashed Potatoes & Garlic Mushrooms

If you’re looking for a reliable tri-tip steak recipe that yields steakhouse-quality results at home, this one delivers. Tender, flavorful, and simple to prepare, tri-tip is a favorite for both quick weeknight dinners and weekend gatherings. Serve it with creamy mashed potatoes and garlicky mushrooms for a satisfying meal that doesn’t require hours in the kitchen.

Tri-tip, a triangular cut from the bottom sirloin, has grown in popularity because it’s versatile, budget-friendly compared to premium steaks, and delicious when cooked correctly.

Steakhouse-style tri-tip steak dinner with mashed potatoes and sautéed garlic mushrooms, plated for serving
close-up of tri-tip steak served with creamy mashed potatoes and garlicky mushrooms on a dinner plate

Keep the seasoning simple so the natural beef flavor can shine. With a light seasoning and careful cooking to the right temperature, this tri-tip will become your go-to for everything from casual family meals to special occasions.

What Makes This Tri-Tip Steak Recipe Special

This recipe emphasizes simplicity and technique. I recommend organic grass-fed tri-tip seasoned with salt, freshly ground pepper, and chopped rosemary. No elaborate marinades are needed—quality ingredients and proper cooking are enough. The rosemary adds a subtle, earthy aroma that pairs nicely with the beef.

Use a meat thermometer to remove uncertainty: aim for 130–135°F for medium-rare. That way you won’t need to cut into the steak and lose precious juices.

close-up of juicy grass-fed tri-tip steak on a cutting board, seasoned with salt, pepper, and fresh rosemary
Sliced grilled tri-tip steak with rosemary and cracked black pepper, cooked medium-rare

If you don’t have a thermometer, see the Recipe Substitutions & Questions section for tips on checking doneness by touch and other cooking methods like stovetop or oven.

How to Cook Tri-Tip Steak on the Grill

Grilling tri-tip is straightforward. High heat produces a caramelized crust while keeping the interior juicy. Follow these steps for consistent results:

1. Pat the tri-tip dry with paper towels—this helps achieve a good sear. Season generously on all sides with salt, pepper, and chopped rosemary.

2. Preheat the grill to high. When hot, place the tri-tip on the grates and cook about 10–12 minutes for medium-rare, flipping halfway through. Use a meat thermometer to confirm 130–135°F for medium-rare, 135–145°F for medium.

3. Remove the steak when it reaches your target temperature and let it rest 5–10 minutes so the juices redistribute. Slice thinly against the grain for the most tender bites.

Steakhouse-style tri-tip steak dinner with mashed potatoes and sautéed garlic mushrooms, plated for serving

The Perfect Side: Creamy Mashed Potatoes

While the tri-tip rests, finish the mashed potatoes. Mini potatoes work well because they’re naturally creamy and cook quickly. Boil until fork-tender (about 15 minutes), drain, and mash in the pot.

Stir in unsweetened almond milk (or your preferred milk) and ghee for a rich, dairy-friendly texture. Season with sea salt and pepper, then garnish with chopped chives and a drizzle of olive oil for a polished presentation.

Creamy homemade mashed potatoes garnished with chopped chives, served in a wooden bowl
Sautéed cremini mushrooms with garlic and Italian seasoning, finished with fresh chives and flaky sea salt

Completing the Meal with Garlicky Mushrooms

Garlicky mushrooms add an earthy, savory element that pairs perfectly with the beef and potatoes. Sauté cremini mushrooms with garlic, a mix of oil and ghee (or vegan butter), then finish with a splash of broth, salt, and Italian seasoning. Top with chopped chives and a sprinkle of flaky salt.

Tips for the Best Tri-Tip Steak Recipe

  • Choose quality meat: Organic, grass-fed tri-tip has a great texture and flavor.
  • Let it rest: Resting keeps the slices juicy—don’t skip it.
  • Slice against the grain: Thin slices across the grain make the steak more tender.
  • Bring to room temperature: Remove the steak from the fridge 30 minutes before cooking for even results.
Steakhouse-style tri-tip steak dinner with mashed potatoes and sautéed garlic mushrooms, plated for serving
Prepped ingredients for making tri-tip steak with creamy mashed potatoes and sautéed garlic mushrooms, ready to cook

Ingredients You’ll Need:

For the Tri-Tip Steak:

  • Organic grass-fed tri-tip steaks
  • Ground pepper
  • Salt
  • Fresh rosemary

To make the Mashed Potatoes:

  • Bag of mini potatoes
  • Unsweetened almond milk (or preferred milk)
  • Ghee
  • Sea salt
  • Ground pepper
  • Chives, to garnish
  • Olive oil, to garnish

For the Garlicky Mushrooms:

  • Avocado oil or extra-virgin olive oil
  • Ghee or vegan butter
  • Garlic cloves
  • Cremini mushrooms
  • Organic chicken or vegetable broth
  • Sea salt
  • Italian seasoning
  • Chopped fresh chives
  • Flaky sea salt, for serving

How To Make Tri-Tip Steak with Mashed Potatoes and Garlicky Mushrooms

Tri-Tip Steak:

Preheat the grill to high. Pat the steaks dry and season generously with salt, pepper, and chopped rosemary. Grill on high heat until desired doneness—about 10–12 minutes for medium-rare—flipping once. Use a meat thermometer for accuracy (130–135°F for medium-rare). Let rest 5–10 minutes, then slice thinly against the grain.

Juicy grass-fed tri-tip steak on a cutting board, seasoned with salt, pepper, and fresh rosemary
Juicy grass-fed tri-tip steak on a cutting board, seasoned with salt, pepper, and fresh rosemary
Grilled tri-tip steak seasoned with rosemary, salt, and pepper, sliced and ready to serve

Mashed Potatoes:

Boil the bag of mini potatoes in salted water until fork tender, about 15 minutes. Drain and return them to the pot. Mash to your desired texture, then stir in milk, ghee, salt, and pepper. Serve topped with chives and a drizzle of olive oil.

mini potatoes in a large pot
Fluffy mashed mini potatoes with ghee and almond milk, topped with fresh chives and olive oil drizzle
Fluffy mashed mini potatoes with ghee and almond milk, topped with fresh chives and olive oil drizzle
Creamy mashed mini potatoes with almond milk, ghee, and garnished with chives and olive oil
Creamy homemade mashed potatoes garnished with chopped chives, served in a wooden bowl

My Kitchen Essentials

Garlicky Mushrooms:

In a large skillet over medium heat, warm the oil and ghee. Add minced garlic and cook 1 minute until fragrant. Add halved cremini mushrooms and cook 3–5 minutes, tossing occasionally. Pour in broth, add salt and Italian seasoning, reduce to medium-low, and simmer about 10 minutes, stirring occasionally. Serve immediately with chopped chives and flaky sea salt.

Garlicky mushrooms ready to be cooked in ghee and olive oil
Sautéing cremini mushrooms with garlic and Italian seasoning
Garlicky mushrooms cooking in ghee and olive oil
Garlicky mushrooms cooked in ghee and olive oil, garnished with chopped chives, served warm
Sautéed cremini mushrooms with garlic and Italian seasoning, finished with fresh chives and flaky sea salt

To Serve and Store:

Serve the sliced tri-tip alongside the mashed potatoes and garlicky mushrooms for a complete steakhouse-style meal. Store each component separately in airtight containers: steak and mashed potatoes up to 3–4 days, mushrooms 2–3 days. Reheat gently before serving.

Tri-tip steak served with creamy mashed potatoes and garlicky mushrooms on a dinner plate

Recipe Substitutions & Questions

Can I cook tri-tip in the oven? Yes. Sear the tri-tip in a hot cast-iron skillet for 2–3 minutes per side, then transfer to a 425°F oven and roast until it reaches your desired internal temperature.

Substitute for ghee? Regular butter, vegan butter, or extra olive oil all work well and will alter the flavor slightly but still taste great.

Can I use regular milk instead of almond milk? Absolutely. Dairy milk or plant-based alternatives (oat, cashew, coconut) will all produce creamy mashed potatoes.

No fresh rosemary? Use about 1 teaspoon of dried rosemary or substitute fresh thyme, oregano, or a touch of garlic powder.

How to check doneness without a thermometer? Try the finger test: press the center of the steak. For medium-rare, it should feel similar to the fleshy area below your thumb when you touch your thumb to your middle finger.

Can this be made ahead? Mashed potatoes can be made up to two hours ahead and kept warm. For best texture and temperature, cook the tri-tip just before serving.

This tri-tip steak dinner is reliable, comforting, and easy to prepare. Proper seasoning, correct cooking temperature, and simple sides make it a go-to recipe for home cooks who want steakhouse flavor without the fuss. Enjoy your meal!

Steakhouse-style tri-tip steak dinner with mashed potatoes and sautéed garlic mushrooms, plated for serving

Other High-Protein Recipes for Dinner:

  • Crockpot Teriyaki Meatballs
  • Freezer-Friendly Beef Enchiladas
  • Miso-Ginger Glazed Salmon with Coconut Rice
  • Healthy Turkey Taco Chili with Butternut Squash
  • High-Protein Chicken Pesto Parmesan Meatball Subs
  • Shawarma Chicken Thighs with Charred Scallion Sauce
  • Smokey Garlic Ginger Chicken Thighs with Roasted Asparagus

Tri-Tip Steak with Mashed Potatoes and Garlicky Mushrooms

By Rachael DeVaux
Prep: 15
Cook: 35
Total: 50
Servings: 3 – 4
Tri-tip steak served with creamy mashed potatoes and garlicky sautéed mushrooms on a plate, steakhouse-style dinner
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A juicy, flavorful tri-tip paired with creamy mashed potatoes and garlicky mushrooms—easy to make and great for home entertaining.

Ingredients

For the Tri-Tip Steak:

  • 1-2 organic grass-fed tri-tip steaks
  • Ground pepper
  • Salt
  • Fresh rosemary

For the Mashed Potatoes:

  • 1 bag mini potatoes
  • ½ cup unsweetened almond milk, or your preferred milk
  • 2 tablespoons ghee
  • 1 teaspoon sea salt
  • 1 teaspoon ground pepper
  • Chives, to garnish
  • Olive oil, to garnish

For the Garlicky Mushrooms:

  • 1 tablespoon avocado oil or extra-virgin olive oil
  • 1 tablespoon ghee or vegan butter
  • 2 garlic cloves, peeled and minced
  • 1 pound cremini mushrooms, halved
  • ½ cup organic chicken broth or vegetable broth
  • ½ teaspoon sea salt
  • ½ teaspoon Italian seasoning
  • 2 tablespoons chopped fresh chives
  • Flaky sea salt, for serving

Instructions

Tri-Tip Steak:

  • Preheat grill to high heat.
  • Pat steaks dry and season generously with salt, pepper, and chopped rosemary.
  • Grill until desired doneness, about 10–12 minutes for medium-rare. Use a meat thermometer for best results (130–135°F for medium-rare).
  • Let rest 5–10 minutes, then slice thinly against the grain.

Mashed Potatoes:

  • Boil mini potatoes in water until fork tender, about 15 minutes.
  • Drain and return potatoes to the pot, then mash.
  • Add milk, ghee, salt, and pepper; mix to combine.
  • Serve with chives and a drizzle of olive oil.

Garlicky Mushrooms:

  • Heat oil and ghee in a large skillet over medium heat.
  • Cook garlic 1 minute until fragrant.
  • Add mushrooms and cook 3–5 minutes, tossing occasionally.
  • Add broth, salt, and Italian seasoning. Reduce heat to medium-low and cook about 10 minutes.
  • Serve topped with chives and flaky salt.

To Serve & Store:

  • Serve sliced tri-tip with mashed potatoes and garlicky mushrooms.
  • Store components separately in airtight containers: steak and potatoes 3–4 days, mushrooms 2–3 days. Reheat gently before serving.

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