4. Fry the Bomboloni:
In a deep pan or Dutch oven, heat about 3 inches of vegetable oil to 350°F (175°C). To test if the oil is ready, drop in a small piece of dough; it should sizzle and rise to the surface immediately.
Fry the bomboloni in batches, making sure not to overcrowd the pan. Fry each one for about 2-3 minutes on each side until golden brown.
Use a slotted spoon to remove the doughnuts and place them on a plate lined with paper towels to drain excess oil.
5. Fill the Bomboloni:
Once the bomboloni are cooled slightly but still warm, use a pastry bag fitted with a small round tip to pipe the chilled pastry cream into the center of each doughnut. Gently insert the tip into the side of the doughnut and fill it with cream.
6. Coat the Bomboloni:
Roll each filled bombolone in granulated sugar while they are still warm, ensuring they are evenly coated.
Tips for the Best Bomboloni alla Crema:
Don’t rush the proofing: Be sure to give the dough enough time to rise for the lightest, fluffiest bomboloni. If the dough isn’t fully risen, it might be dense.
Frying temperature is key: Make sure the oil stays at a consistent temperature of around 350°F (175°C). Too hot, and they will burn on the outside while staying raw inside; too cool, and they will absorb too much oil and become greasy.
Filling the Bomboloni: You can test the filling by gently pressing on the doughnut to see if it gives slightly when you insert the pastry tip. Don’t overfill them, as they may burst.
Make-ahead: You can prepare the pastry cream a day in advance, and the dough can also be made ahead and kept in the fridge for a slow rise overnight.