Add the cocoa powder, chocolate chips, baking powder and sea salt into a mug and mix.
Add the rest of the cake ingredients and mix to combine.
Microwave for 2 minutes, stopping to check for doneness at 90 seconds and every 15 seconds after that. Microwaves vary so time may be different. Mine took 2 full minutes.
You can also divide the batter into two mugs and cook it a little less, start checking at 1 minute.
Allow to set and cool and devour! Top with optional ingredients if preferred.
To make the chocolate sauce, simply add all ingredients into a microwave safe container and heat at 20 second increments, stirring in between, until melted throughout!
Notes
This is meant to have a deep dark chocolate flavor. To make it sweeter use sweet chocolate chips.
Microwaves very so make sure you do not over cook. The cake is meant to be gooey and chocolaty, not like a firm traditional cake.
If you add marshmallows, add them at 90 seconds so they can melt a bit.