Warm 1 cup of whole milk to 110–120°F. Stir in 2 tablespoons of granulated sugar, then sprinkle 2 teaspoons of active dry yeast over it. Let sit for 5–10 minutes until foamy.

Mix in 6 ounces of sourdough discard, 2 large room-temperature eggs, and 4 tablespoons of softened salted butter. Add a dash of ground nutmeg and mix until smooth.

Gradually add 3–4 cups of all-purpose flour at low speed until the dough forms a loose ball. Dust with flour if sticky.

Transfer the dough to a greased bowl, cover it, and let rise until doubled in size, about 1 hour.

Roll out to ½-inch thickness on a floured surface. Cut out donuts and place on parchment-lined sheets. Let rise again until doubled, about 1 hour.

Heat 3–4 cups of oil to 375°F in a deep fryer or heavy pot.

Fry donuts in batches for 1–2 minutes per side until golden brown. Drain on paper towels.

Mix 1 cup of powdered sugar, 2 tablespoons of milk, and a pinch of salt for the glaze until smooth.

Dip cooled donuts in glaze and set on a cooling rack.