Preheat oven to 350°F and line a muffin tin with cupcake liners or grease with coconut oil spray. Set aside.
In a medium bowl, whisk together almond flour, coconut flour, erythritol, baking powder, baking soda, and salt
In a separate bowl, mix eggs, melted butter, stevia, and vanilla. Add the wet ingredients to the dry ingredients and mix until just combined.
Divide the batter between the cupcake liners, filing them ¾ of the way full. Bake for 20-25 minutes, until a toothpick inserted in the middle of a cupcake comes out clean.
Allow to cool completely prior to frosting.
Frosting
Add the butter to a large bowl and beat with a hand mixer until fluffy.
Next, add cocoa powder, swerve and vanilla to the bowl. Beat until thoroughly mixed and smooth.
If frosting is too thick, beat in milk alternative or cream, 1 tbsp at a time until frosting reaches desired consistency.
Cupcakes are best stored in an air tight container in the fridge up to 10 days.
Note: the nutrition below is for each frosted cupcake if all the frosting was used. If you don't use all the frosting the macros (fat grams in particular) will be much lower.