In a sauce pan or wide sauté pan, heat fat over medium-low heat.
Whisk in flour. Cook for 1-2 minutes. Slowly add in milk, about 1/3 at a time, whisking constantly. Bring up to a simmer.
Add beef bouillon, stir to dissolve. Season with salt & pepper to taste. Simmer until thickened.
Serve hot over biscuits.