Add the first three ingredients to a small mixing bowl and stir to combine.
Melt butter in a small bowl in a microwave for several seconds. Add low carb sweetener and stir until completely dissolved. Add egg, heavy cream, vanilla extract, and salt to the butter mixture and whisk to combine.
Add wet ingredients to the dry and stir until thoroughly blended. Pour blended mixture into a mug or small microwave-safe container and microwave on high for 1 minute.**
Remove from microwave and serve immediately with fresh sliced strawberries, if desired. Enjoy!