Melt 1 tablespoon of butter in a microwave for 45 seconds. Allow to cool.
Whisk egg and add sweetener, vanilla extract, and salt, whisking again to combine.
Add cooled butter to egg mixture, whisk to combine.
In a separate bowl, combine almond flour, cacao powder, and baking powder. Add this to egg mixture and whisk.
Heat a small sauté pan over medium heat. Add 2 squares of Lily's chocolate and 1/2 tablespoon of butter, stirring frequently.
Pour cake mixture in a bowl or mug of choice, reserving 2 tablespoons. Add 1 square of Lilly's chocolate to center of cake and top with the remaining cake mixture. Microwave for 60–80 seconds.
Invert cake onto serving plate and pour the melted chocolate from the sauté pan on top.
Serving Size 1 cake
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.