In a bowl, whisk warm evaporated milk, warm milk, 1 tbsp sugar, and yeast. Rest 8 to 10 minutes until foamy.
In a stand mixer with hook attachment, add bread flour, remaining sugar, salt, eggs, and the foamy yeast mixture. Mix until dough forms.
Add softened butter gradually and knead 8 to 10 minutes until smooth and elastic.
Place the dough in a large bowl. Cover with a kitchen towel or plastic wrap. Let it rise in a warm place for about one hour or until doubled in size.
After the dough has risen, punch it down, reshape into a ball, cover, and let it rise again for another hour.
Roll dough on a floured surface to ¾-inch thick. Cut ovals or circles. Place on a baking sheet, cover, and rise 30 minutes until puffy.
Heat 2 inches of oil to 360 to 375°F. Fry donuts 1 to 2 minutes per side until golden.
Transfer fried donuts to a baking sheet lined with paper towels or a wire rack. Cool before rolling the malasadas in sugar.
Optional: To fill, poke with a chopstick and wiggle around a little to create a cavity inside. Fill a pastry bag with your choice of filling and stuff the donut until it is firm and plump.