Heat A Large Skillet Over Medium-High Heat. Add Ground Beef, Add Onions, Garlic, And Mushrooms; Saute Until Onion Is Golden Brown. Season With Salt And Black Pepper. Stir 2 Cups Hot Water, Bouillon Cubes, And Tomato Paste Into Meat Mixture. Stir Together 1 1/2 Cups Cold Water And Flour; Stir Into Pan. Reduce Heat To Low, And Simmer For 1 Hour.