Slow-Cooker Sour Cream Portobello Tenderloin Tips Step-by-step instructions

Before you start

Before you start, trim any excess fat from the beef tenderloin tips if needed. Thickly slice the portobello mushroom caps and peel the shallots, cutting any large ones in half. Measure out the sour cream and have the brown gravy mix ready.

If you're serving the dish with egg noodles, cook them according to the package directions just before the slow cooker finishes. Set out your 6-quart slow cooker and a large spoon for layering the ingredients.

Instructions

Layer and Cook Low

1. 1Layer the Raw Ingredients
   Place the beef tenderloin tips in the bottom of a 6-quart slow cooker. Scatter the thickly sliced portobello mushroom caps over the beef, then add the peeled and halved shallots. Spread the sour cream over the top, then sprinkle the brown gravy mix evenly over everything.
   Look for The beef is covered with mushrooms, shallots, sour cream, and gravy mix.
   Tip No need to stir—the layers will meld as they cook.
2. 2Cover and Cook Low
   Cover the slow cooker and cook on low for 8 hours, or on high for 4 hours, until the beef is fork-tender and the sauce is bubbling and thickened. Let it rest for 3 minutes before slicing.
   Look for The sauce will be bubbling gently around the edges.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Resist lifting the lid—it releases heat and slows cooking.

At the end of the first phase, the slow cooker is filled with raw beef, mushrooms, shallots, sour cream, and gravy mix. The sour cream and gravy mix form a thick paste on top.

As the slow cooker heats, you'll see gentle bubbling around the edges. The aroma is savory and earthy, with hints of onion and beef. The ingredients are not yet cooked through, but the sauce is beginning to melt and combine.

Check and Rest

3. 3Check the Beef Temperature
   After cooking, check that the beef has reached at least 145°F (63°C) on an instant-read thermometer. Let the beef rest in the warm sauce for at least 3 minutes before serving.
   Look for The beef is fork-tender and the sauce is thick and glossy.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip The rest allows the juices to redistribute.
4. 4Stir the Sauce
   Gently stir the sauce to combine the sour cream and gravy mix into a smooth, velvety gravy. The sauce should coat the back of a spoon.
   Look for The sauce is uniform, rich, and slightly thickened.
   Tip If the sauce seems thin, let it cook uncovered for 10 minutes more.

After 8 hours on low, the sauce is bubbling and has turned a rich mahogany color. The beef is fork-tender and easily pulls apart, and the mushrooms are soft and glossy. The shallots are translucent and sweet. The sauce coats the back of a spoon. The beef has reached at least 145°F (63°C), and the dish is ready to rest before serving.

Serve Over Noodles

5. 5Serve Over Buttered Noodles
   Spoon the hot beef, mushrooms, and shallots over warm buttered egg noodles. Ladle extra gravy over each serving.
   Look for The noodles are coated with the creamy gravy.
   Tip Warm the noodles just before serving.

The beef and sauce are spooned over warm buttered noodles, with extra gravy ladled over each serving. The dish is steaming and fragrant, with tender beef, meaty mushrooms, and sweet shallots in a creamy, glossy sauce. The noodles are evenly coated, and every bite is rich and satisfying. The plate is ready to serve immediately.

Common mistakes

A common mistake is lifting the lid during cooking, which releases heat and extends the cooking time. Another is using low-fat sour cream, which can separate or curdle more easily than full-fat. Make sure the beef is fully submerged in the sauce as it cooks—if it's exposed, it can dry out.

Also, don't skip the resting time after cooking; it's important for the meat's texture. Finally, resist the urge to stir too early; let the layers meld undisturbed for the first few hours.

How to tell it’s done

The dish is done when the beef is fork-tender and easily shreds with a fork, and the sauce has thickened to a velvety consistency. An instant-read thermometer inserted into the thickest piece of beef should register at least 145°F (63°C).

After cooking, let the beef rest in the warm sauce for at least 3 minutes before serving to allow the juices to redistribute. The mushrooms should be tender but still hold their shape, and the shallots should be soft and sweet.

• Steaks, chops and roasts: 145°F (63°C) in the thickest part, then a 3-minute rest