Preheat the oven to 350 F and grease an 8 inch cast iron skillet or square baking pan. In a large bowl whisk the almond flour, coconut flour, baking powder, salt, and baking soda.
In a separate bowl beat the eggs, melted butter, sour cream, erythritol, and almond milk until smooth.
Pour the wet mixture into the dry ingredients and stir just until combined. Fold in the shredded cheddar for extra moisture and savory depth.
Spread the batter evenly in the prepared pan. Bake for 25 to 30 minutes until the top is golden and a toothpick inserted in the center comes out clean.
Cool for 10 minutes before slicing. The texture should be moist, tender, and lightly crumbly like classic cornbread.