Combine the corn flour and corn meal in a medium bowl. Add the buttermilk, and stir well to combine. Cover and refrigerate overnight or up to 2 days.
Preheat oven to 375. Coat a 10” cast iron skillet with the 2 tsp bacon fat and place in the oven while it preheats.
In a small bowl, whisk the flour, powder and soda and set aside.
In a large bowl, whisk together both sugars, the eggs, honey and salt. Whisk in the cornmeal mixture and combine well. Add the flour mixture and stir with a spatula until completely incorporated. Mix in the melted butter, and finally the bacon.
Remove skillet from oven and immediately pour in the batter. Smooth the top and return to the oven promptly. Bake for 35-45 minutes, rotating the skillet about halfway through cooking time. The cornbread should be deep brown on top and a skewer or knife inserted into the center should come out with a few moist crumbs.