Cowboy Butter Portobello Tenderloin Tips: Slow-Cooker Dinner Tips, FAQ & printable recipe

Tips for success

For the best flavor, use a good-quality garlic-herb cowboy butter, whether store-bought or homemade. If making your own, let the butter come to room temperature and mix in minced garlic, fresh parsley, thyme, and a pinch of smoked paprika for extra depth.

If you prefer a spicier kick, add a dash of cayenne or a few red pepper flakes. The butter not only adds richness but also helps create a silky sauce as it melts.

When serving, use a slotted spoon to lift the beef and vegetables, then ladle the sauce over the top. This keeps the mashed potatoes from becoming too soupy. If you have leftovers, store them in an airtight container in the refrigerator for up to 4 days.

The flavors continue to meld, making the leftovers even more delicious. Reheat gently on the stovetop or in the microwave, adding a splash of beef broth if needed to loosen the sauce.

Variations

• Add Bacon: Cook 4 slices of bacon until crisp, crumble, and sprinkle over the finished dish for a smoky, salty crunch. This adds another layer of flavor that complements the beef and mushrooms.
• Use Chicken: Substitute boneless, skinless chicken thighs for the beef tenderloin tips. Cook on LOW for 4 to 5 hours, until the chicken is tender and reaches 165°F (74°C). Adjust the au jus mix if needed.
• Spicy Kick: Add 1 to 2 teaspoons of hot sauce or a pinch of cayenne pepper to the butter before adding it to the slow cooker. This gives the dish a gentle heat that balances the richness.
• Vegetarian Version: Replace the beef with extra portobello mushrooms and add 1 cup of vegetable broth. Omit the au jus mix and use a mushroom-based seasoning instead. Cook on LOW for 3 to 4 hours, until the mushrooms are tender.

Storage and make-ahead

Fridge

Store in an airtight container in the refrigerator for up to 4 days. The sauce will thicken when cold; add a splash of broth when reheating.

Freezer

This dish freezes well for up to 3 months. Cool completely, then transfer to a freezer-safe container. Thaw overnight in the refrigerator before reheating.

Reheat

Reheat gently on the stovetop over low heat or in the microwave, stirring occasionally. Add a splash of beef broth or water to restore the sauce's consistency.

Store any leftovers in an airtight container in the refrigerator for up to 4 days. The beef and mushrooms will keep their texture, and the sauce will thicken slightly when chilled.

Reheat gently on the stovetop over low heat, or in the microwave in 30-second intervals, stirring occasionally. Add a splash of beef broth or water if the sauce becomes too thick.

This recipe is ideal for making ahead. Assemble the ingredients in the slow cooker insert the night before, cover, and refrigerate. In the morning, place the insert in the slow cooker and cook as directed.

You can also cook the dish fully, let it cool, and refrigerate it for up to 4 days. Reheat gently on the stovetop or in the microwave before serving.

Serving ideas

Serve the cowboy butter portobello tenderloin tips over creamy mashed potatoes to soak up the rich, buttery sauce. The beef and mushrooms are also delicious over egg noodles, rice, or polenta. For a low-carb option, serve alongside roasted vegetables or a simple green salad. The sauce is the star, so make sure to spoon plenty over each serving.

This hearty dish pairs well with a glass of red wine, such as a Merlot or Cabernet Sauvignon, which complements the beefy flavors. For a complete meal, add a side of crusty bread to mop up the sauce. Leftovers can be turned into a delicious sandwich by piling the beef and mushrooms onto a toasted roll and spooning the sauce over the top.

Frequently asked questions

Recipe card

Cowboy Butter Portobello Tenderloin Tips: Slow-Cooker Dinner

Prep 15 minCook 6 hTotal 6 h 15 minServes 6

Ingredients

• 2 lb beef tenderloin tips (or tenderloin medallions, trimmed and cut into 1-inch pieces)
• 8 oz portobello mushrooms, thickly sliced
• 6 shallots, peeled and halved
• 1/2 cup garlic-herb cowboy butter (2 sticks, softened)
• 1 oz dry au jus mix

Instructions

1. Place the beef tenderloin tips in the bottom of a 6-quart slow cooker. Scatter the thickly sliced portobello mushrooms and the peeled, halved shallots over the beef. No need to stir; the layers will meld during cooking.
2. Dot the garlic-herb cowboy butter over the top of the beef and vegetables. Sprinkle the dry au jus mix evenly over everything. Do not add any liquid; the butter and meat juices will create a rich sauce as they cook.
3. Cover the slow cooker and cook on LOW for 6 to 8 hours, or on HIGH for 3 to 4 hours, until the beef is fork-tender and the mushrooms are soft. The sauce will be bubbling and fragrant. Let it rest for 3 minutes before slicing.
4. Once the beef is tender, turn off the slow cooker and let the dish rest for at least 3 minutes before serving. The beef should reach an internal temperature of 145°F (63°C) if you check it. Serve the beef, mushrooms, and shallots with a generous ladle of the buttery au jus over mashed potatoes or crusty bread.

Contains: milk

Estimated nutrition per serving

Calories

580

Protein

38 g

Carbohydrates

12 g

Fat

42 g

Automatic estimate from the ingredient list, not laboratory-verified.