Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or a silicone baking mat to prevent sticking and make cleanup easier.

Unfold the 2 sheets of puff pastry on a lightly floured surface. If there are creases or if the sheets are stuck together, gently press with a rolling pin just enough to smooth the surface without thinning the dough too much.

If the puff pastry sheets are not exactly the same size, trim them so they match. You want two rectangles or squares that line up neatly so they twist and bake evenly.

Place one puff pastry sheet on your work surface. Spread 1/2–3/4 cup Nutella evenly over the surface, leaving about a 1/2-inch border around the edges so it doesn’t leak out while twisting.

If using chopped hazelnuts, mini chocolate chips, or a light sprinkle of cinnamon, scatter them evenly over the Nutella layer, keeping the border clear to help the edges seal.

Carefully place the second puff pastry sheet directly over the Nutella-covered sheet, lining up the edges. Gently press around the border with your fingers to seal the layers together.

Slide the stacked pastry onto the prepared baking sheet. Working directly on the pan makes cutting and twisting easier and keeps the dough from stretching too much.

Using a sharp knife or pizza cutter, slice the stacked pastry into 10–12 long strips about 1–1 1/2 inches wide. For a ring shape, leave a small uncut section at one short end, keeping it intact like a hub, and cut the strips outward from there.

Twist each strip gently several times so the Nutella shows in spirals. For a wreath, twist each strip and turn it slightly outward to form a ring. For straight twists, simply twist and arrange them in a line or braid if desired.

In a small bowl, whisk together the egg and milk or cream. Brush the mixture lightly over the surface of the pastry. If you like a crunchy top, sprinkle with vanilla sugar or granulated sugar.

Bake for 18–23 minutes, or until the pastry is deeply golden brown and well puffed. The Nutella should look set and the edges crisp. Start checking around 16–17 minutes, as ovens vary.

Let the pastry cool on the pan for at least 10 minutes. This allows the Nutella to firm up slightly so the twist slices more cleanly without the filling squeezing out.

Dust the cooled pastry lightly with powdered sugar. Garnish with extra chopped nuts or fresh berries if desired, then slice and serve warm or at room temperature.