Preheat oven to 425°F.
In a small bowl, mix soy milk and lemon juice to make vegan buttermilk.
In a medium bowl, sift together flour, sugar, cocoa powder, cinnamon, nutmeg, and salt. Add buttermilk, egg, and vegan butter; stir until just combined - batter should be light and airy.
Fill each doughnut cup halfway with batter. Clean any batter from the center of each cup to ensure doughnuts bake with a hole in the middle.
Bake at 425°F for 4 to 6 minutes, or until the top of the doughnuts bounce back when touched.
While doughnuts cool in the pan for 4 to 5 minutes, make vanilla glaze topping. In a small bowl, whisk sugar, soy milk, and vanilla extract until sugar is completely dissolved and mixture is thick.
Place doughnuts on a cooling rack. Use a spoon to drizzle each with vanilla glaze.
As published in Joy of Kosher with Jamie Geller magazine (Bitayavon Winter 2011) - Subscribe Now