In a small bowl combine warm water (about 38–43°C / 100–110°F) and warm milk with 1 teaspoon of the sugar. Sprinkle the instant yeast over the liquid and let sit 5–8 minutes until foamy.

In the bowl of a stand mixer fitted with the dough hook (or a large bowl if mixing by hand), combine the flour, remaining sugar, and salt. Mix briefly to combine.

Add the foamy yeast mixture, eggs, and olive oil to the flour. Mix on low until ingredients come together, then increase speed to medium and knead 4–5 minutes until a rough dough forms.

Add softened unsalted butter, 1 tablespoon at a time, allowing each to incorporate before adding the next. Continue kneading 6–8 minutes until the dough is smooth, elastic and slightly tacky but not sticky. (If too wet, add up to 1–2 tablespoons extra flour.)

Transfer dough to a lightly oiled bowl, cover with plastic wrap or a towel, and let rise in a warm place until doubled, about 60–75 minutes.

Shaping & Proofing

Turn the risen dough out onto a lightly floured surface. Press gently to deflate and roll to a 1-inch (2.5 cm) thick slab.

Using a 3-inch round cutter, cut donuts. Use a 1-inch cutter to cut centers. Re-shape scraps lightly and reroll once to cut additional donuts. You should get about 12 standard-size donuts.

Place cut donuts on a baking sheet lined with parchment, spacing 1–2 inches apart. Cover loosely and let proof at room temperature until puffy and nearly doubled, 30–40 minutes.

Nduja Butter

While donuts proof, make the nduja butter: In a small bowl combine the softened butter and nduja. Use a fork to mash and blend until homogeneous. Taste and adjust heat—add more nduja for spicier spread or a little softened butter to tame it.

Fold in 30 g of the grated Parmesan, fennel pollen, Sicilian oregano, 1/2 teaspoon flaky sea salt, and freshly ground black pepper. Mix until evenly distributed. Transfer the nduja butter to plastic wrap and shape into a log; refrigerate until firm, about 30 minutes. Reserve remaining Parmesan for garnish.

Frying & Finishing

Heat neutral oil in a deep pot or heavy-bottomed skillet to 175°C (350°F). Use a candy/deep-fry thermometer for accuracy. There should be at least 2 inches (5 cm) of oil depth.

Working in batches (do not overcrowd), gently slide 2–3 proofed donuts into the hot oil. Fry 60–75 seconds per side until golden brown, flipping halfway. Total fry time will be about 2–2.5 minutes per donut depending on thickness.

Use a slotted spoon to remove donuts and drain on a wire rack set over a baking sheet. While still warm, brush the tops lightly with 1–2 teaspoons of water to help the nduja butter adhere.

Slice each donut horizontally (like a sandwich) or make a single slit. Spread about 1 tablespoon of the nduja butter inside each donut (more if desired).

Sprinkle the remaining grated Parmesan over the exposed butter, then dust each donut with a light pinch of fennel pollen and Sicilian oregano. Finish with a light sprinkle of flaky sea salt and a crack of black pepper.

Serve warm so the nduja butter is slightly melty. Store leftover nduja butter refrigerated and reheat donuts briefly in a 160°C (325°F) oven to refresh before serving.