Preheat the oven to 350 degrees. Add the black sesame seeds to a food processor or blender. Pulse until a fine powder remains.
In a bowl combine the sweet rice flour, brown sugar, black sesame seed powder, baking powder, and salt.
In another bowl, combine the butter, almond milk, eggs, and vanilla. Whisk to combine.
Gently sift the dry ingredients into the wet ingredients. Fold them together until they are just combined. Don't overmix!
Transfer the mixture to a piping bag or ziploc bag (with a hole cut in one corner). Grease two mini donut pans*. Pipe the mixture into the donut pans, with each donut filling about 3/4 of the pan.
Bake at 350 for 13-15 minutes. Let cool for 5 minutes and then transfer onto a cooling rack.
While the donuts cool, make the icing. Combine the powdered sugar and milk and whisk to combine. If the icing isn't as thin as you want, add another splash of milk. Dip each donut into the icing and transfer back to the cooling rack to let any additional icing drip off.
Top with extra black sesame seeds and enjoy!