Preheat the oven to 350 F degrees F. Line the bottoms of three 6-inch OR two 8-inch or 9-inch round cake pans with parchment paper rounds, then spray with nonstick baking spray. Set aside.

In a mixing bowl, whisk together almond flour, coconut flour, baking powder, baking soda, and salt set aside.

In a separate large bowl, combine eggs, erythritol, buttermilk, cooled butter, lemon juice, zest, and extracts. Mix until thoroughly combined.

Slowly add the dry ingredients to the wet and mix until combined. Allow to sit a couple minutes so the coconut flour can absorb the liquid.

Divide the batter evenly between the prepared baking pans and bake for 20-25 minutes, until a toothpick comes out clean.

Allow the cakes to cool in the pan for at least 30 minutes before transferring to wire racks to cool completely. Remove the parchment paper liner and frost as desired.

In a mixing bowl or stand mixer, beat cream cheese and butter for 4-5 minutes, until smooth and creamy. 

Add the powdered erythritol and mix until smooth and creamy.

Add heavy cream, zest, extracts, and salt. Mix until fluffy, adding more cream if desired for a smoother frosting.

Spread the frosting between the cake layers and on sides using a spatula. Serve or refrigerate until ready to serve.