MAKING THE GRAVY: Add the additional oil and garlic to the same skillet and sauté until fragrant, about 1 minute. Whisk in the flour and continue to cook for about 2 minutes. Then gradually add the beef stock while continuously whisking. Once incorporated together, add the butter, sherry vinegar, beef bouillon, onion powder, and bay leaf. Simmer, while whisking, for about 4 minutes or utilize it was thickened. Taste, and season with salt and pepper if needed.