1 pound ground beef
1 small onion, diced
2 cloves garlic, minced
1 can (10.75 ounces) condensed cream of mushroom soup
1 cup beef broth
1 tablespoon Worcestershire sauce
1 teaspoon Dijon mustard
1 cup sliced mushrooms
1/2 cup sour cream
Salt and pepper to taste
Cooked egg noodles or rice, for serving
Fresh parsley, chopped (optional, for garnish)