Nutella Bomboloni 7 Steps
In a large bowl, add bread flour, 00 flour, granulated sugar, salt and yeast. Using a whisk, mix until evenly incorporated. Scatter cubed butter over flour and pour in beaten eggs, milk and vanilla extract. Using a wooden spoon, mix until wet ingredients are absorbed by flour mixture and dough starts to resemble a shaggy mound. Pour out onto a clean work surface and start kneading until a dough ball beings to form.
Knead dough with the palm of your hand for 10 minutes or until a smooth and elastic ball is formed (depending on the time of year and the humidity in the room you may need to adjust dough's consistency with more or less flour and more or less milk).
Place dough ball in a lightly oiled, medium-sized bowl and cover with plastic wrap. Let rise in a warm place for 2 hours, or until tripled the size.
Once dough has risen, remove from bowl onto clean work surface and punch down slightly a few times to get rid of air bubbles. Form back into a smooth ball and roll out into a large oval (roughly 1/2-inch thick). Using a round cutter or a glass measuring around 4-inches, cut out circles from dough. Place on parchment-lined baking sheet, 1-inch apart from each other and re-roll scraps, cut out circles again and place on sheet. Cover with plastic wrap and let rise in a warm place for 1-2 hours (you should have roughly 10 rounds).
Once rounds have risen and puffed up nicely they are ready to fry! In a heavy-bottomed pot or Dutch oven, fill up halfway with vegetable oil. Heat your oil to 350°F. While oil is heating up, cut 10 squares out from your parchment paper that is lining the baking sheet (each bomboloni should be on a square of parchment).
Have another baking sheet lined with paper towel ready for your bomboloni and place a medium shallow bowl filled with superfine sugar beside your stovetop. Using a slotted spoon, slowly lower bomboloni (on square of parchment paper) into the hot oil (working in batches of 3-4). Remove parchment with tongs. Fry each bomboloni for 1 1/2 to 2 minutes on each side. Remove from hot oil onto paper towel, let cool slightly and then place in bowl of superfine sugar, flip to other side, moving bomboloni so it is evenly coated in sugar.
Once you are finished frying and coating the bomboloni, let cool for 15-20 minutes. To fill, use a serrated knife to cut into side of doughnut, making a large enough incision to fill the bomboloni. Fill a pastry bag with Nutella and pipe Nutella into centre of bomboloni. Bomboloni are best enjoyed day of!