In a small mixing bowl, whisk flour, unsweetened cocoa powder, coconut sugar, baking powder, and sea salt until combined.
Add olive oil, almond milk, and vanilla. Whisk until smooth.
Stir in chocolate chips if desired.
Transfer the batter into a tall microwave-safe coffee mug and sprinkle a few extra chocolate chips on top.
Microwave for 80-90 seconds at 900W or until cooked on top, not runny in the center. You can return to the microwave by 10 seconds burst if undercooked. Also, if your microwave works at lower power, you may have to increase baking time by 20 seconds bursts. If your mug is low and wide, your mug cake will bake faster, and you may have to bake only 60 seconds first, then adjust baking by 20-second bursts.
Enjoy immediately, mug cakes baked in the microwave don't store well.
Sugar-free option: replace sugar with the same amount of erythritol and use sugar-free chocolate chips.Gluten-free flours: you can use all-purpose gluten-free flour, but the cake won't rise! Gluten is the active ingredient that raises the cake when combined with baking powder, so any gluten-free flour will make this cake flat and dense.