Preheat oven to 350 degrees. Melt 1 tablespoon butter in a 9 to 10 inch cast iron skillet over medium heat.

In a large bowl, whisk together almond flour, coconut flour, baking soda, and sweetener.

In another bowl, whisk together eggs and heavy cream. Slowly add butter. 

Stir wet ingredients into the dry ingredients until just combined. 

Transfer batter to skillet and smooth the top.

Bake for 30 minutes or until the cornbread is golden.