Step 1

Cut the beef into one-inch cubes and pat completely dry. Discard any large pieces of fat. Fat that’s marbleized into the meat is fine!

Step 2

Season with garlic salt and pepper. Sprinkle with flour and toss to coat.

Step 3

Heat 2 Tablespoons olive oil in a skillet over medium-high heat. Sear the meat in batches for 45 seconds per side, until browned but not cooked through. Use kitchen tongs to carefully remove and set aside on a plate. Add more olive oil between batches as needed and decrease heat slightly if the pan gets too hot.

Step 4

Add 1 Tablespoon butter and white wine to the pot over medium heat. Use a silicone spatula to “clean” (deglaze) the bottom of the pan. Add the onions and mushrooms and cook for 4 minutes. Add the minced garlic and cook for 1 more minute. Remove from heat.

Step 5

Add the beef broth, bouillon, red wine vinegar, Worcestershire sauce, and Dijon mustard to the Slow Cooker and stir to combine. Add the beef as well as any juice that may have dripped onto the plate. Add the onions/mushrooms/garlic.

Step 6

Cook on high for 4-5 or on low for 8-9 hours.

Step 7

Combine the cornstarch/cold water mixture and whisk it into the Slow Cooker.

Step 8

Flip to warm.

Step 9

In a medium bowl, whisk sour cream with 1 cup liquid from the slow cooker until smooth. Add to Slow Cooker and stir carefully to combine.

Step 10

Stir in the condensed cream of mushroom soup if desired. (My homemade version adds even more thickness and flavor.)

Step 11

Finally, turn heat off and swirl in 2 Tablespoons of cold butter. This adds a smooth, velvety finish.

Step 12

Serve over egg noodles. If desired, add cooked/drained egg noodles right to the Slow Cooker, stir to combine, and serve!