Cook sausage in large skillet over medium-high heat 8-10 minutes or until thoroughly cooked, stirring frequently. Stirring frequently; drain and set aside.
Preheat oven to 400°F.
Place sausage in lightly greased 13x9-inch baking pan; top with onions and cheese.
Beat eggs, half-and-half and baking mix with wire whisk until well blended.
Pour over cheese.
Bake 20-25 minutes or until knife inserted in center comes out clean.
Cool 5 minutes.
Cut into 12 squares.
Add toppings.
