Preheat your oven to 325°F (163°C) and grease a 13x9x2-inch baking dish.

Cook 1 pound of lean ground beef and ½ cup of chopped onions in a skillet over medium heat for 5-7 minutes. Drain fat and add taco seasoning, tomato sauce, and 1 cup of corn. Spread in prepared baking dish and top with 2 cups of cheese.

In a bowl, whisk together 2 cups of Bisquick mix, 1 cup of milk, and 2 large eggs until smooth. Pour over the meat and cheese layers.

Bake for 35 minutes or until the crust is golden brown. A knife inserted into the center should come out clean.

Cool for 10 minutes, cut into squares, and serve with toppings.