First, in a small bowl or liquid measuring cup, combine the almond flour, cinnamon, baking soda (or baking powder), and salt. Whisk everything together until it's well mixed.
Next, add the applesauce, honey (or maple syrup), avocado oil (or coconut oil), vanilla extract, and the egg. Stir vigorously until you have a smooth, well-combined batter.
Pour the batter into a microwave-safe mug (ideally 6-8 ounces) or use the measuring cup you mixed it in for fewer dishes!
Place the mug in the center of your microwave. Cook on high for 1 to 2 minutes. (For a 900-watt microwave, 90 seconds is usually perfect. Adjust time based on your microwave's power.)
Your mug cake is ready when it looks puffy and a toothpick inserted into the center comes out clean.
Let it cool for a couple of minutes.