Preheat the oven to 350°F (175°C). Line a 6-cup muffin pan with paper or silicone liners.

Beat the eggs in a stand mixer until well mixed.

Add the unsweetened cocoa powder, almond flour, melted butter, sweetener, baking powder, and salt. Beat until a smooth batter has formed.

Divide the batter evenly between the liners. Bake for 18-20 minutes, until a toothpick inserted in the center comes out clean.

Let the cupcakes cool completely on a wire rack, at least 30 minutes, before frosting.

For the frosting, beat the softened cream cheese and butter together until smooth. Add the vanilla extract and powdered sweetener, then beat again until smooth and fluffy. If it seems soft, chill it for 15-20 minutes.

Spoon the frosting into a piping bag fitted with a large round or star tip. Pipe a ring around the edge of each cupcake, then two smaller rings on top, and lift the bag straight up to form the ghost's pointed head.

Press the chocolate chips into the frosting to make two eyes and a mouth on each ghost.

Serve right away, or store in an airtight container in the fridge until needed.