Dinner · Part 3 of 3: Tips & recipe card

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

Name: Cowboy Butter Pepper Tenderloin Tips: Slow-Cooker Dinner
Prep time: 10 min
Cook time: 6 h
Total time: 6 h 10 min
Cuisine: American
Ingredients: 2 lb beef tenderloin tips; 1 green bell pepper, sliced into thick strips; 1 red bell pepper, sliced into thick strips; 1 red onion, cut into wedges; 2 sticks garlic-herb cowboy butter (store-bought or homemade); 1 oz dry au jus mix (1 packet)

By Clara Weller · Oct 28, 2026

Slow-cooker beef tenderloin tips with peppers and onions in a rich golden sauce, served in a black ceramic crockpot

Prep: 10 min
Cook: 6 h
Total: 6 h 10 min
Serves: 6

Tips for success

For the most flavorful sauce, use a high-quality au jus mix and a good cowboy butter. If you have time, you can make your own cowboy butter by mixing softened butter with minced garlic, chopped parsley, chives, and a pinch of cayenne or smoked paprika.

Let it firm up in the fridge before adding it to the slow cooker. The butter not only adds flavor but also enriches the sauce, giving it a velvety texture.

This recipe is perfect for meal prep. Cook a double batch and freeze half for later—the flavors actually improve after a day or two in the fridge.

When reheating, add a splash of beef broth to loosen the sauce if it has thickened too much. Serve with creamy mashed potatoes, buttered noodles, or crusty bread to soak up every last drop of the savory gravy.

Variations

Mushroom & Herb: Add 8 oz sliced mushrooms with the peppers and onions. Use a herb butter with thyme and rosemary for an earthy flavor. The mushrooms will release extra moisture, creating an even richer sauce.
Spicy Kick: Add 1-2 sliced jalapeños or a teaspoon of crushed red pepper flakes with the vegetables. Use a cowboy butter with a hint of chipotle or cayenne for a smoky heat that complements the beef.
Beef & Broccoli: Replace the bell peppers with 2 cups broccoli florets. Add them during the last 30 minutes of cooking to keep them crisp-tender. The broccoli will absorb the butter-au jus sauce beautifully.
Balsamic Glaze: Stir 2 tbsp balsamic vinegar into the sauce before serving. The acidity brightens the rich, buttery gravy and adds a touch of sweetness. Garnish with fresh parsley for color.

Storage and make-ahead

Fridge: Store leftovers in an airtight container in the refrigerator for up to 4 days.
Freezer: Freeze in a freezer-safe container for up to 3 months. Thaw overnight in the refrigerator before reheating.
Reheat: Reheat gently on the stovetop over medium-low heat, adding a splash of beef broth to thin the sauce if needed.

Leftovers can be stored in an airtight container in the refrigerator for up to 4 days. The sauce will thicken as it cools; add a splash of beef broth or water when reheating to restore the desired consistency.

You can prep the ingredients the night before: cut the beef, slice the peppers and onions, and measure the butter and au jus mix. Store them separately in the refrigerator, then assemble everything in the slow cooker in the morning. Cook on low for 6 to 8 hours, and you’ll have dinner ready when you need it.

Serving ideas

This dish is hearty enough to stand on its own, but it truly shines when served over a bed of creamy mashed potatoes. The sauce soaks into the potatoes, making every bite rich and satisfying.

For a lighter option, serve it over rice, quinoa, or even cauliflower mash. A side of crusty bread is perfect for mopping up the extra sauce.

For a complete meal, add a simple green salad or roasted vegetables on the side. The savory, buttery flavors of the beef and peppers pair well with bright, acidic sides like a lemon vinaigrette or pickled onions.

If you have leftovers, shred the beef and use it in tacos, sandwiches, or over a baked potato for an easy lunch the next day.

Frequently asked questions

Can this recipe be made with a different cut of beef?

Yes, you can use sirloin tips, chuck roast cut into chunks, or even beef stew meat. The slow cooker will tenderize these cuts over the long cooking time, though the texture will be slightly different from tenderloin. Adjust the cooking time as needed—chuck may benefit from the full 8 hours.

What is cowboy butter and where can it be found?

Cowboy butter is a compound butter made with butter, garlic, herbs, and often spices like smoked paprika or cayenne. It's available in many grocery stores in the dairy or meat sections, or you can make your own by mixing softened butter with your favorite seasonings. If you can't find it, use regular butter plus a teaspoon of garlic powder and a pinch of dried herbs.

Can this recipe be cooked on high instead of low?

You can cook it on high for 3 to 4 hours, but the beef may not be as tender as when cooked on low. The low setting allows the connective tissue to break down slowly, resulting in a more succulent texture. If you're short on time, high heat will still produce a tasty meal, but check for doneness earlier.

How can the sauce be thickened if it's too thin?

If the sauce is too thin after cooking, remove the beef and vegetables with a slotted spoon, then transfer the sauce to a saucepan. Bring it to a simmer over medium heat and cook until reduced by about a third. Alternatively, whisk a tablespoon of cornstarch with two tablespoons of cold water and stir it into the simmering sauce until thickened.

Can this recipe be made without a slow cooker?

Yes, you can use a Dutch oven or a heavy pot with a lid. Brown the beef in batches over medium-high heat, then add the vegetables, butter, and au jus. Cover and cook in a 300°F (150°C) oven for 2 to 3 hours, or until the beef is fork-tender. Check occasionally and add a little beef broth if needed.

Recipe card

Cowboy Butter Pepper Tenderloin Tips: Slow-Cooker Dinner

Prep 10 minCook 6 hTotal 6 h 10 minServes 6

Ingredients

2 lb beef tenderloin tips
1 green bell pepper, sliced into thick strips
1 red bell pepper, sliced into thick strips
1 red onion, cut into wedges
2 sticks garlic-herb cowboy butter (store-bought or homemade)
1 oz dry au jus mix (1 packet)

Instructions

Place the beef tenderloin tips in the bottom of the slow cooker. Scatter the green bell pepper strips, red bell pepper strips, and red onion wedges over the beef. Place the two sticks of garlic-herb cowboy butter on top of the vegetables, then sprinkle the dry au jus mix evenly over everything.
Cover the slow cooker and cook on low for 6 to 8 hours, until the beef is fork-tender and the sauce is bubbling and rich. The butter will melt into the au jus, creating a golden gravy that coats the meat and vegetables. Let it rest for 3 minutes before slicing.
Turn off the slow cooker. Let the beef rest in the sauce for at least 3 minutes before serving. Use a slotted spoon to transfer the beef and vegetables to a serving dish, then spoon the sauce over the top. Serve hot over mashed potatoes or with crusty bread.

Contains: milk

Estimated nutrition per serving

Calories: 420
Protein: 28 g
Carbohydrates: 8 g
Fat: 30 g

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

Next recipe

Bourbon gravy pepper tenderloin tips in a slow cooker with tender beef and peppers in glossy gravy

Dinner · 6 h 10 min

Bourbon Gravy Pepper Tenderloin Tips: Easy Crockpot Dinner

See the recipe → →

This recipe is based on a short cooking video and is published under the pen name Clara Weller. It was checked before publication, but errors can slip through. Nutrition, when shown, is an estimate. Read more in our editorial policy and on our food safety page.