Heat oven to 375 degrees. In a skillet, melt the butter over medium heat. Cook until the butter turns a deep nut brown, swirling the pan to coat the sides.
STEP 2
Pour brown butter into a large bowl. Whisk in the maple syrup and then the buttermilk. Let cool before whisking in the eggs. Then whisk in cornmeal, flours, baking powder, salt, and baking soda.
STEP 3
If the skillet is cooled, reheat it briefly on the stove. Scrape batter back into it. Bake until the top is golden and a toothpick inserted comes out clean, about 30 to 40 minutes. Cool in the skillet for 10 minutes before slicing.