Pre-heat oven to 400°F.
Place a large skillet on the stove and turn the heat to medium.
Add the ground beef and onion; cook for a few minutes until the beef becomes brown and the onion is translucent; drain excess oil.
Apply cooking spray in a 9-inch pie pan.
Transfer the beef mixture into the prepared pie pan.
Sprinkle a generous amount of cheese on top of the beef mixture.
In a medium mixing bowl, add the Bisquick, onion soup mix, eggs, and milk; whisk until well mixed.
Spread the mixture over the beef mixture in the pie pan.
Place it inside the pre-heated oven and bake for about 25 minutes or until done.
Remove the Cheeseburger Pie from the oven and allow it to cool at room temperature for about 3 to 5 minutes.
Loved the Cheese Burger Pie. We had enough for a second meal and it was excellent.