Preheat your oven to 400°F (200°C) and line a muffin tin with paper liners. Roll out the puff pastry into a rectangle on a floured surface, then brush melted butter evenly over it.

Combine sugar and cinnamon in a bowl and sprinkle it over the buttered pastry.

Roll the pastry into a tight log from the longer side, slice into 1-inch thick segments, twist each segment, and place them upright in the muffin tin.

Bake the Churro Cruffins for about 20 minutes until golden brown and puffed. Watch closely to prevent over-browning.

Let the muffin tin sit for 5-10 minutes before cooling to prevent the filling from melting away.

Create a small hole in the top of each cruffin and fill with dulce de leche.

Sprinkle remaining cinnamon-sugar mixture over the filled cruffins before serving.