Dissolve the yeast in warm milk with a pinch of sugar and let it sit until foamy.
Mix sugar, eggs, flour, and salt, then gradually add the butter until the dough becomes smooth and elastic.
Cover the dough and let it rise for 90 minutes until doubled in size.
Punch down the dough, roll it out, and cut into rounds.
Let the shaped donuts rise for another 30–40 minutes until puffy.
Heat oil to 365°F and fry each donut 1–2 minutes per side until golden brown.
Drain on a rack and coat with sugar or drizzle with glaze while warm.