Preheat oven to 350 degrees. In a large bowl whisk together the almond flour, coconut flour, Erythritol, baking powder, cinnamon, and sea salt.
Stir in the beaten eggs, vanilla extract, softened cream cheese, melted butter, and almond milk. (You can also use a stand mixer for a smoother batter - just reverse the order and start with the wet ingredients).
Divide the batter evenly among 12 greased muffin tins (use butter). Top with equal portions of the crumb topping (pile higher in the center - then press down lightly) and bake for 20-25 minutes or until a tester comes out clean.
Place the muffins on a cooling rack for 10 minutes. Use a piping tool to top with frosting, or just drizzle.
Combine all ingredients in a medium bowl. You can use a fork or even pulse gently in a food processor until crumbs are formed.
Mix powdered sweetener (Sukrin Melis) with cream cheese in a small bowl. Add the vanilla extract and heavy cream and stir until smooth.
Each muffin has only 3g of net carbs. To reduce the carb content you can eliminate the frosting.