Impossibly Easy Cheeseburger Pie (Gluten Free)

This recipe is from the Bisquick Gluten Free site.

1 lb lean (at least 80%) ground beef
1 medium onion, chopped
1/2 teaspoon salt
1/8 teaspoon pepper
1 cup shredded GOAT Cheddar cheese (4 oz)
1/2 cup Bisquick® Gluten Free mix (this is sold in most grocery stores now by the regular Bisquick, I have seen it at the Folsom Target, Raley’s, Bel Air, Winco and more)
1 cup rice or goat milk
3 eggs

1. Heat oven to 400°F. Spray 9-inch glass pie plate with cooking spray (olive oil spray from Trader Joe’s). In 10-inch skillet, cook beef and onion over medium-high heat, stirring frequently, until beef is thoroughly cooked; drain. Stir in salt and pepper. Spread in pie plate; sprinkle with cheese.
2. In medium bowl, stir Bisquick mix, milk and eggs until blended. Pour into pie plate.
3. Bake 25 to 30 minutes or until knife inserted in center comes out clean.