Romagna Donut

Break the eggs into a bowl, add the fine sugar and the softened butter. Work the mixture with a fork until you obtain a smooth mass, without obvious streaks of butter and with a soft and uniform consistency.

Place the flour on the cutting board Forming a fountain, that is, gathering it with a central hollow large enough to contain the liquid ingredients. This arrangement facilitates the gradual incorporation of the mixture and limits dispersion during kneading.

Pour into the center of the fountain the mixture of eggs, sugar, and butter, then add the milk. Knead with your hands until you obtain a compact, smooth dough, free of dry particles; work just enough so that the dough is soft and malleable.

Add the grated lemon zest, the cream of tartar and the baking sodaKnead again to distribute them evenly: the lemon scent should be diffused and there should be no areas of concentrated dust.

Butter the baking pan and transfer the dough into it. Spread it out into a ring shape and make a well-defined hole in the center, maintaining a uniform thickness to promote even cooking.

Beat the egg yolk and brush it over the surface of the donut, coating it evenly. Top with sprinkles, ensuring they adhere to the yolk; the surface should be completely shiny and decorated before baking.

Bake the donut at 180°C (356°F) for 30 minutes. Check for doneness by observing the surface, which should appear golden and firm; the cake should retain its ring shape and be dry on the outside.