Preheat a heavy, deep pan over medium-high heat with olive oil. Add ground beef and stir to break down beef into tiny pieces. Add onions and minced garlic. Saute until the onion is translucent and golden brown.

Add sliced mushrooms and saute for another 5 minutes or until the mushrooms soften. If they release a lot of juice, let it evaporate.

Add flour and stir until fully incorporated. Be sure to mix in any lumps that form.

Add 1 cup beef broth, 1 cup whipping cream, 1 tablespoon Worcestershire sauce, ½ teaspoon salt, and ½ teaspoon black pepper and bring it to a simmer. Turn the heat to low and simmer for about 5 minutes.

Remove from the heat and add in sour cream. Stir to combine everything together and season to taste if needed. Serve over noodles, rice or potatoes.