Preheat oven to 400°F.

Add ground beef and onion to a large skillet and cook until beef is browned and onion is softened. Drain grease. Spread mixture in a 9-inch pie dish.

Sprinkle cheese over the cooked meat.

In a medium bowl, whisk together milk, onion soup mix, Bisquick, and eggs. Pour the mixture into the pie dish over the meat and cheese.

Bake for 25 minutes. Let cool for a few minutes before serving.