Preheat the oven to 375 degrees Fahrenheit and grease the donut pan.
In a small bowl, combine the ground flax meal and water. Let sit for 5 minutes before adding to mixture.
In a large bowl, whisk together the flour, cocoa, baking powder, baking soda, salt, and sugar.
In a separate bowl, combine the milk, melted coconut oil, vanilla, and flax egg and thoroughly mix.
Pour the wet ingredients into dry ingredients and mix to combine.
Use a piping bag or a large Ziploc bag to pipe the mixture into the donut pan (if you do not have piping bags just spoon the dough into a gallon ziplock bag and cut 1 corner off).
Bake for 10 minutes, until the tops of the donuts are springy (aka they bounce back if you touch them).
Remove donuts oven and let cool in the pan for 3-5 minutes before removing to cool fully on a wire rack. Once cooled store donuts in the fridge in an airtight container.
In the microwave, heat 2 tbsp of nut butter for about 30-45 seconds, until slightly melted.
Add the maple syrup to the nut butter and thoroughly mix. The mixture should be thick enough to hold its shape on the top of the donut.
Drizzle on the tops of the donuts with a spoon or small ziplock bag. Serve immediately.