Cornbread & Peppers with butter

2 cups yellow cornmeal 1 cup flour 1 1/2 tablespoons baking powder 1 1/2 teaspoons salt 2 tablespoons brown sugar 3 eggs 1 1/3 cups milk 1/2 cup butter ,[...]

8 tablespoons chilled unsalted butter , cut into 1/2 inch pieces 1 cup chopped onion 1 3/4 cups yellow cornmeal 1 1/4 cups all-purpose flour 1/4 cup sugar 1[...]