Prepare the ramekins. Preheat the oven to 350°F (175°C). Lightly grease two oven-safe ramekins and place them on a baking sheet.

Combine the dry ingredients. Whisk together the coconut flour, sweetener, cocoa powder, and baking powder, breaking up any lumps.

Melt the chocolate. Melt the chopped chocolate and coconut oil together in short microwave intervals, stirring frequently, or gently over a water bath. Let cool slightly.

Mix the batter. In a separate bowl, whisk the eggs with 3 tablespoons of coconut milk. Gradually whisk in the warm chocolate mixture, then stir in the dry ingredients until combined. If the batter is dry or too stiff to spoon easily, add the remaining tablespoon of coconut milk.

Add the filling. Divide the batter evenly between the ramekins, leaving room for it to rise. Place 1 tablespoon of peanut butter in the center of each cake and gently press it into the batter without pushing it to the bottom.

Bake. Bake for approximately 13–15 minutes, until the edges are set and the cake surrounding the peanut butter is baked but still soft. Baking time depends on the ramekin size and material.

Serve. Let rest briefly, then serve warm directly from the ramekins.