Cut sirloin steak into 1" pieces and place in a medium sized bowl.Mix 1 tbsp flour, seasoned salt and pepper in a small bowl. Toss flour mixture with the beef cubes and stir to coat all beef pieces well. Shake off any excess flour.
Spray large frying pan with generous amount of olive oil spray and heat pan to medium heat.
Brown sirloin pieces in the pan with olive oil spray (in small batches so pan is not overcrowded), turning pieces so all sides are brown but not cooked through. Spray pan again with olive oil spray between batches if needed. Beef will still be pink inside.
Remove sirloin pieces to a plate.
Melt butter in frying pan and add shallots. Cook over medium to medium high heat until tender.
Add garlic and cook for about one minute.
Stir mushrooms into shallot/garlic mixture and cook for about 4 minutes or until the mushrooms are softened, stirring occasionally.
Add remaining 2 tbsp flour to mushroom mixture and cook for about one minute.
Stir in the beef broth, Worchestershire sauce, Dijon mustard, red wine, and dried thyme. Bring mixture to a boil, reduce heat to a simmer and cook for 5 minutes until mixture is hot and bubbly.
Add beef with juices, if any, and 3 tbsp fresh chopped parsley and cook for another 2 minutes or until the beef is heated through. If sauce appears to be too thick you may add a little additional beef broth.
Remove pan from the heat and stir in sour cream and plain Greek yogurt. Add additional salt and pepper to taste if desired.
Serve over cooked egg noodles or bow tie pasta (optional) and garnish with additional fresh chopped parsley. Additional serving suggestions to cut down on calories and carbs: serve with whole grain pasta, mashed potatoes or zucchini noodles.
Calories based on 6 servings and does not include pasta.