1. Brown the ground beef in a large skillet over medium-high heat, breaking up the meat as it cooks. Drain excess fat and set the beef aside.
2. In the same skillet, melt the butter over medium heat.
3. Slowly add the flour to the melted butter, stirring constantly, to form a brown roux.
4. Add the beef bouillon to the roux.
5. Gradually stir in the milk and Worcestershire sauce, mixing well to combine.
6. Return the cooked ground beef to the skillet and add salt and pepper to taste.
7. Bring the mixture to a simmer, stirring constantly.
8. Serve the SOS hot over buttered toast.

Enjoy this comforting and hearty dish, reminiscent of the classic US Army fare!