Turn on an oven to preheat to 350 F (180 C). Add egg whites to a stand mixer and whip them until they become opaque white and foamy. Then, whip powdered erythritol and vanilla extract into the egg whites. Continue whipping until you have medium-stiff peaks.
Step 2
Make sure your almond flour is sifted and not clumpy. In 2-3 additions, whip the almond flour into the egg whites. It’s important you don’t deflate the egg whites with heavy ingredients. Melt the butter, then slowly pour it into the batter while you continue whipping the ingredients.
Step 3
It’s best to use silicone molds for these cakes, but you may also use a muffin tray. Add the batter to a piping bag or a plastic Ziploc bag with the corner cut off. Use your bag to squeeze the batter into your cake molds. Each cake should use about 2 tablespoons of batter.
Step 4
Add approximately ¼ teaspoon of sliced almonds on top of each cake (these will be the tops, not the bottoms). Place your filled molds or muffin tray on a baking sheet. Then, bake the cakes for 25 minutes or longer. The edges will be lightly golden, and you can use a toothpick to test for doneness. Remove the cakes from the molds after cooling for 5-10 minutes.