Preheat oven to 400 F. Lightly butter an 8-inch glass baking dish. Set aside.
Whisk together cornmeal, flour, baking powder, salt, baking soda, cinnamon, clove, nutmeg, granulated sugar, and brown sugar in a large bowl. Set aside.
Combine pureed sweet potatoes, eggs, egg yolk, butter, oil, vanilla, and buttermilk in a large bowl. Stir in orange food coloring if using.
Gradually add dry ingredients to wet ingredients, stirring just until combined. Do not over stir.
Pour batter evenly into the prepared pan.
Bake on the middle rack for 20 minutes. After 20 minutes, tent with foil and bake for an additional 20 minutes or until the middle is set.
Remove from oven and make the glaze.
To prepare the glaze, stir together all of the glaze ingredients. Stir the brown sugar into the butter while it's hot so that it dissolves.
Brush the glaze generously over the hot cornbread a few times.
Serve.
Notes
See note on how to prepare the sweet potato puree.