In a medium bowl, add the butter, agave, egg, and vanilla.
Whisk the wet ingredients until combined.
Add the almond flour, oat flour, baking powder, salt and sprinkles to the bowl.
Whisk in the dry ingredients until combined.
Divide the batter between two mugs and add a pinch of extra sprinkles to the tops of each.
Microwave each mug for 1 minute. Some microwaves may take more time so if the mug cake looks a bit wet around the edges, put it back in for another 30 seconds.
Top with whatever you want! I added some whipped cream and more sprinkles (always!).