In a mixing bowl, combine egg, sour cream, milk, oil, sugar, and vanilla.
Mix well until incorporated.
Add in flour, cocoa powder, salt and baking powder and stir until incorporated.
Add in chocolate chips if using.
Grease your mini or regular sized donut pan well. If you don't have a donut pan, use a mini cupcake pan. Same taste just no hole. Grease it well.
Bake at 375 for 8-10 minutes for mini donut pan or mini cupcake pan and 10-12 minutes for a larger donut pan. or until a toothpick inserted comes out not wet.
Allow donuts to cool for 5 minutes.
Flip them out onto a wire rack or pastry board. Allow them to cool.
Make <g class="gr_ gr_156 gr-alert gr_gramm gr_inline_cards gr_run_anim Grammar only-ins doubleReplace replaceWithoutSep" id="156" data-gr-id="156">glaze</g> by combining powdered sugar, milk and vanilla and mixing until smooth.
I like to divide my glaze, one for the first dunk and one for the second dunk...So no crumbs are in the 2nd dunk.
Dunk each donut in the glaze, place on a wire rack for them to set. Once they are dry (<g class="gr_ gr_171 gr-alert gr_gramm gr_inline_cards gr_run_anim Grammar only-ins replaceWithoutSep" id="171" data-gr-id="171">first</g> dunk gets mostly absorbed) dunk them a second time and allow that glaze to dry.
Enjoy that day or the next.