Impossible Broccoli 'n' Cheddar Pie

2 (10 ounce) packages frozen chopped broccoli
3 cups shredded Cheddar cheese (12 ounces), divided
2/3 cup chopped onion
1 1/3 cups milk
3 eggs
3/4 cup Bisquick
3/4 teaspoon salt
1/4 teaspoon pepper

Heat oven to 400 degrees F. Grease a 10-inch pie plate.

Rinse broccoli under running cold water to thaw; drain thoroughly. Mix broccoli, 2 cups of the cheese and onion in plate. Beat milk, eggs, baking mix, salt and pepper until smooth, 15 seconds in blender on high or 1 minute with hand beater. Pour into plate. Bake until knife inserted in center comes out clean, 25-35 minutes.

Top with remaining cheese. Bake just until cheese is melted, 1 to 2 minutes longer. Cool 5 minutes.

Yields 6 to 8 servings.