In a microwave-safe mug, combine the butter and cream cheese. Microwave on 50% power for 30-45 seconds, stirring halfway through, until just melted and combined. Be careful not to overheat.

Add the coconut flour, sweetener, and baking powder to the mug. Stir vigorously with a fork until a thick paste forms. Ensure no dry pockets of flour remain.

Whisk in the egg, maple extract, and vanilla extract until the batter is smooth and well incorporated. Scrape down the sides of the mug to include all ingredients.

Gently press the frozen raspberries into the center of the batter. This prevents them from coloring the entire cake.

Microwave on high for 60-90 seconds, or until the cake is cooked through and springs back when lightly touched. Cooking time may vary based on microwave wattage.