Fill a heavy bottomed pot or Dutch oven (or a deep fryer) with 8+ cups of vegetable oil and heat to 350° (use a thermometer to ensure accurate temperature).
In a medium mixing bowl, combine 1 tbsp ground flax and 2.5 tbsp water and set aside to gel.
In large mixing bowl, combine 1 ⅓ cups of flour, ½ a cup of sugar, ¼ cup of cocoa powder, ½ tsp baking soda and ¼ tsp salt, and whisk.
To the flax mixture, add 6 tbsp of vegan sour cream, ¼ cup of plant milk, ¼ cup of vegetable oil, and 1 tsp of vanilla, and whisk.
Make a well in the centre of the dry ingredients and pour in the wet mixture. Stir together using a spatula or wooden spoon until a dough forms.
Turn the dough out onto a lightly floured surface and work into a ball using your hands.
Roll out the dough with a rolling pin until it's roughly ½" thick, then dip your donut cutter into some flour to prevent sticking and cut out donuts. If you don't have a donut cutter, use a water glass or round cookie cutter to cut out the circles of dough and a smaller cookie cutter or a chopstick (poke it into the centre and keep the tip pressed against the counter, then hula hoop the donut around the chopstick) to make the hole in the centre of each donut.
Continue cutting out donuts until there are only scraps left, then form a new dough ball with the scraps and roll out again to cut out additional donuts. Alternately, make the scraps into donut holes and fry them after you're done frying the donuts.
Before you begin frying the donuts, place a cooling rack over a baking sheet or a paper towel on a plate, so the donuts have somewhere to cool and drain.
Once your oil is hot, carefully place two-three donuts max in the oil. They will sink to the bottom and slowly rise up. Fry the donuts on each side for 1½-2 minutes before flipping over and frying for another 30 seconds. Remove them from the oil using a spider or tongs and place them on the rack to cool completely.
Once you've fried all the donuts and the donuts holes, it's time to make your glaze. Whisk together the icing sugar, plant milk, and vanilla until smooth. Add an extra tablespoon of milk if your glaze is too thick.
Once cooled, dip the donuts and donut holes in the glaze and return them to the rack to drip dry.
