Preheat the oven to 375°F (190°C) and line a muffin tray with cupcake liners.
In a large mixing bowl, combine the almond flour with coconut flour, cocoa powder, Erythritol, baking powder, baking soda, and sea salt. Whisk to combine.
In another bowl, combine the buttermilk with the melted butter and vanilla extract. Add the eggs and whisk well.
Combine the two mixtures and whisk to get a smooth batter. Gradually add the red food coloring until you reach the desired shade of red. It depends on the pigment, but in most cases, 1-2 teaspoons should be enough. The color will get darker in the oven.
Divide the mixture into the prepared muffin tray and bake in the oven for 15-20 minutes.
Make the buttercream frosting or cream cheese frosting while the cupcakes are baking. Allow the cupcakes to cool to room temperature before frosting.