Heat oven to 375.
Spray regular size muffin tip with cooking spray
In a skillet brown hamburger and onion until cooked through. Drain
Cool for 5 minutes and add in Worcestershire sauce, garlic salt and cheese.
In a bowl mix together milk Bisquick and eggs. Whisk with a fork
Spoon 1 scant tablespoon of baking mixture into each muffin cup
Top with 1/4 C hamburger mixture
Spoon 1 tablespoon baking mixture over top of hamburger mixture
Bake for 20-30 minutes until toothpick comes out clean and they are golden brown.
Run a knife around edge if needed to remove from muffin tin
Top with tomato, ketchup and mustard