Impossible Broccoli Pie
["2 pkg. frozen chopped broccoli (10 oz.)", "3 c. shredded Cheddar cheese (12 oz.)", "2/3 c. chopped onion", "1 1/3 c. milk", "3 eggs", "3/4 c. buttermilk baking mix", "3/4 tsp. salt", "1/4 tsp. pepper"]
["Heat oven to 400\u00b0.", "Grease pie plate (10 x 1 1/2-inches). Rinse broccoli to thaw; drain.", "Mix broccoli, 2 cups of the cheese and onion in pie plate.", "Beat milk, eggs, baking mix, salt and pepper until smooth (15 seconds in blender on high or for 1 minute with hand beater).", "Pour into plate.", "Bake approximately 25 to 35 minutes (or until knife comes out clean).", "Top with remaining cheese.", "Bake just until the cheese is melted (approximately 1 to 2 minutes longer).", "Let stand 5 minutes.", "Garnish with tomato slices."]
["broccoli", "Cheddar cheese", "onion", "milk", "eggs", "buttermilk baking mix", "salt", "pepper"]