Stir the yeast and 1 teaspoon of the sugar into the milk, then set it aside for about 10 minutes until the mixture looks foamy.
Add the yeast mixture to a bowl along with the flour, vegan butter, lemon zest, remaining sugar, and nutmeg. Knead for a few minutes by hand or with a stand mixer until you get a soft, smooth dough. Cover and let it rise in a warm place for about 30 minutes.
Divide the dough into six equal pieces and shape each into a ball. Let them rest for another 30 minutes. Then poke a hole into the center of each ball using your fingers or a small round cookie cutter and gently stretch it a little. The hole will shrink slightly as they fry.
Heat enough oil in a pot so at least one donut can float freely. Medium heat works best for me, around level 6–7. Carefully lower the donuts into the hot oil and fry for about 40 seconds per side, until golden brown. Remove and drain on paper towels or a wire rack.
While the donuts are still warm, add your toppings. Dip them into melted chocolate or toss them in cinnamon sugar until well coated. Let the topping set briefly, then enjoy while they’re fresh.