Gather your ingredients and tools to ensure a smooth process.
In your mug, combine the all-purpose flour, baking powder, sea salt, and ground cinnamon. Stir until well mixed.
Add in the pure maple syrup, creamy peanut butter, milk, and vanilla extract. If using, add the avocado oil now. Mix until you have a smooth batter.
Gently fold in the semi-sweet chocolate chips.
Place the mug in the microwave and cook on high for about 1 minute, adjusting time as needed.
Let it cool for a minute, then enjoy your mug cake!