Mix masa harina, almond flour or gluten-free flour, sea salt, sugar, and baking powder and mix until combined.
Next, add egg, oil, and mix in the buttermilk mixture. Mix until just combined.
If using a cast-iron pan, add 1 tablespoon of oil to the pan and place in the preheated oven until it melts. Next, add the cornbread batter, smooth the top, and bake at 400 degrees for 25-28 minutes.
Alternative: Use a greased pie pan, or an 8x8 pan lined with parchment, add the cornbread batter and bake at 400 degrees for 25-28 minutes.