Activate Yeast: In a small bowl, mix warm milk, sugar, and yeast. Let it sit 5–10 minutes until foamy.
Mix Dough: In a large bowl, combine flour and salt. Add eggs, melted butter, and yeast mixture. Knead until smooth (8–10 minutes by hand or 5 minutes with a stand mixer).
First Rise: Cover dough and let it rise in a warm place for 1–2 hours or until doubled in size.
Shape Donuts: Roll dough to ½-inch thickness. Cut into donuts with a donut cutter or two round cutters. Place on a floured tray.
Heat Oil: Heat vegetable oil in a deep pan to 350°F (175°C).
Fry Donuts: Carefully fry donuts 1–2 minutes per side until golden brown. Remove with a slotted spoon and drain on paper towels.
Add Toppings: While warm, dust with powdered sugar, cinnamon sugar, or drizzle with chocolate glaze.