Prepare the Dough:

In a large mixing bowl or stand mixer, combine the flour, salt, and sugar. Create a well in the center.

Pour the warmed milk into the well and sprinkle the crumbled fresh yeast (or dried yeast) over the milk. Let it sit for 5 minutes until foamy.

Add the softened butter and beaten eggs to the bowl.

Knead the dough on low speed (or by hand) for about 8 minutes until the dough is smooth and silky.

First Rise:

Form the dough into a smooth ball and place it in a greased bowl. Cover with a damp cloth.

Let the dough rise in a warm, draft-free place for about 90 minutes or until doubled in size.

Shape the Bomboloni:

Roll the dough out onto a lightly floured surface to about 1/2-inch thickness.

Use a 2¼-inch cookie or biscuit cutter to cut out rounds.

Place the rounds on a parchment-lined baking sheet and cover with a light cloth. Let them rest for 10 minutes (or 5 minutes in a warm kitchen).

Fry the Bomboloni:

Heat about 1 inch of vegetable oil in a deep pan over medium-low heat to 350°F (175°C).

Fry the bomboloni in small batches, 5-6 at a time, until golden brown on both sides. Flip carefully with a slotted spoon.

Drain on paper towels and allow to cool slightly.

Fill the Bomboloni:

Use a small paring knife to make a slit in the center (or side) of each bombolone, creating a pocket for the filling.

Fill a piping bag or small Ziploc bag with custard (or your chosen filling), snip the tip, and pipe about a teaspoon of filling into each pastry.

Finish and Serve:

Dust the filled bomboloni generously with powdered sugar.

Serve warm or at room temperature.