Step 1

Heat 1 tablespoon of the oil in a 10-inch skillet. Add the onions, mushrooms, and garlic. Cook over medium heat, stirring occasionally, until the onions are tender. Remove from the skillet.

Step 2

Combine ¼ cup of the flour, salt, and pepper in a large bowl. Add the beef strips and toss to coat. Transfer the beef to a plate, shaking off any excess flour.

Step 3

Return the skillet to the stove over medium-high and add the remaining oil.

Step 4

When the oil is hot, add the beef to the pan in a single layer. Cook for 2 minutes, until golden brown. Flip the beef and sprinkle it with the remaining tablespoon of flour.

Step 5

Add the beef stock, mustard, Worcestershire sauce, paprika, and peppercorns. Simmer 10 minutes, until the gravy is thickened.

Step 6

Return the mushrooms and onions to the pan and remove from heat.

Step 7

Add the sour cream to a small dish. Stir in a few tablespoons of the gravy to warm it up (this will prevent it from curdling.) Stir the warmed sour cream into the Stroganoff, stirring constantly.

Step 8

Taste and adjust the seasoning as needed. If the flavors seem flat, a generous pinch of salt will help bring it together and perk everything up.