If you do a 'search' on the web for 'Mug Cakes', you'll find a variety of recipes. I've tried quite a few. Some I like; others found their way into the rejection bin! I found this recipe and with a little change, it has become one of my favorites. 

• 1/4 cup spelt or whole wheat pastry flour
• 2 T dark unsweetened cocoa powder (aluminum free)
• 1/4 tsp baking powder
• 2 T granulated sugar ( I use monkfruit)
• 1/8 tsp salt
• 1/4 cup non-dairy milk plus 1 T (I use almond milk, plain, unsweetened)
• 1 T veggie oil (I use avocado)
• 1 T applesauce
• 1 T mini non-dairy chocolate chips

In medium bowl, whisk the dry ingredients well. Then whisk in the non-dairy milk, oil, and applesauce, and mix all ingredients until well combined. Make sure there are no clumps.

Pour the batter into a safe microwave mug. Leave enough head space for cake to rise.

Place the chocolate chips on top of batter. No need to mix in.

Put mug in microwave and cook on high for 1 minute. 

Since all microwaves are different, you'll have to see how it cooks in yours. Mine is 1100 watts and 1 minute was sufficient.