Preheat oven to 375 degrees F (190 degrees C). Grease a 9x13-inch baking dish.
Beat cottage cheese, butter, and eggs in a large bowl. Stir corn bread mixes into butter mixture until just moistened. Fold in broccoli, onion, and 1 cup Cheddar cheese.
Pour batter into prepared baking dish and sprinkle with remaining 1/2 cup Cheddar cheese.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, 35 to 40 minutes. Cool in the baking dish for 10 minutes before slicing and serving warm.
