1. Prepare the Dough

• In a small bowl, mix warm milk and yeast. Let sit for 5-10 minutes until foamy.
• In a large bowl, combine flour, sugar, and salt. Make a well in the center and add the yeast mixture, eggs, melted butter, and vanilla. Stir until a dough forms.

2. Knead the Dough

Transfer the dough to a floured surface. Knead for 5-7 minutes until smooth and elastic.

3. First Rise

Place the dough in a greased bowl. Cover with plastic wrap or a damp cloth and let rise in a warm spot for 1 hour or until doubled in size.

4. Prepare the Pastry Cream

• In a saucepan, heat milk over medium heat until it begins to simmer.
• In a separate bowl, whisk egg yolks, sugar, and cornstarch until smooth. Gradually pour hot milk into the egg mixture, whisking constantly.
• Pour the mixture back into the saucepan and cook on medium heat, stirring until thickened. Remove from heat, stir in butter and vanilla, and let cool.

5. Shape the Bomboloni

• After the dough has risen, punch it down and roll it on a floured surface to ½-inch thickness. Cut out 3-inch circles.
• Place dough circles on a floured baking sheet. Cover and let rise for another 30 minutes.

6. Fry the Donuts

• Heat oil in a deep pot or fryer to 350°F (175°C). Fry donuts in batches for 1-2 minutes per side until golden brown. Transfer to a paper towel-lined plate.

7. Fill with Pastry Cream

Once cooled, fill a piping bag with the pastry cream. Insert the tip into each bomboloni and squeeze gently to fill.

8. Dust with Sugar

In a shallow dish, mix sugar and cinnamon (if using). Roll each filled bomboloni in the sugar until well-coated.