Step 1

Preheat oven to 400 degrees F (200 degrees C). Grease a 10-inch cast-iron skillet, and place it into the oven while it preheats.

Step 2

Place the zucchini, milk, onion, eggs, and vegetable oil into a blender, and pulse 5 to 8 times, until thoroughly mixed and the zucchini and onion have been chopped into very small pieces.

Step 3

Mix together the cornmeal, flour, sugar, baking powder, and salt in a large bowl. Pour the zucchini mixture into the cornmeal mixture, stirring to combine, and gently mix in the Cheddar cheese.

Step 4

Carefully pour the batter into the hot greased skillet, smooth it out with a spoon, and bake until the cornbread is golden brown and a toothpick inserted into the center comes out clean, about 30 minutes.