Prepare the Mug: For each cake, place 1 tablespoon of unsalted butter into its designated mug. Microwave for 20-30 seconds, or just until melted. Swirl the butter to coat the inside walls of the mug.
Whisk the Batter: Into the mug with the melted butter, add one egg, one-third of the almond flour (just under 3 tbsp), ½ teaspoon of baking powder, 1 tablespoon of granular sweetener, a pinch of salt, and a pinch of the nutmeg. Whisk vigorously with a fork directly in the mug until the batter is completely smooth and aerated, about 45 seconds.
Create the Cinnamon Layer: Sprinkle 1 teaspoon of the golden monk fruit sweetener evenly over the surface of the batter. Follow with a generous dusting of ground cinnamon. Do not stir it in; this creates the swirl effect after cooking.
The Microwave Bake: Cook one mug at a time in the microwave on high power for 90 to 105 seconds. The cake is done when the top is set and springs back when lightly touched. Be mindful that overbaking will result in a tough texture.
Melt-In-Place Glaze: Remove the mug carefully—it will be very hot. Immediately drop the softened cream cheese (about ⅔ tbsp), remaining butter (about ⅓ tbsp), and powdered sweetener (about ⅔ tbsp) directly onto the center of the hot cake. Add the splash of optional heavy cream. Let it all sit for 60 seconds to soften and melt from the cake’s residual heat.
Final Swirl & Serve: Using the tip of a spoon or a toothpick, gently swirl the melted glaze ingredients together to create a marbled frosting over the cake's surface. The cake is best enjoyed immediately while it is still warm and fragrant. Repeat the process for the remaining two cakes.
