Preheat oven to 375°F. Generously grease 8 cups of a standard muffin pan with about 1 tbsp of the melted butter, then dust the greased cups lightly with granulated sugar, tapping out any excess.

In a small bowl, whisk together the 1/2 cup granulated sugar, ground cinnamon, and salt until evenly combined. Set aside.

Lightly flour a work surface. Unfold 1 sheet of puff pastry and roll it into a 10-by-14-inch rectangle, keeping the edges as straight as possible.

Brush the rolled pastry with about 2 tbsp of the melted butter, going all the way to the edges. Sprinkle about half of the cinnamon sugar mixture evenly over the buttered surface.

Starting from a long side, roll the pastry up tightly into a log, as you would for cinnamon rolls, keeping the roll even and snug.

Using a sharp knife, trim the very ends if uneven, then slice the log into 4 equal pieces. If layers squash, use a gentle sawing motion without pressing down.

Take each piece, stand it up so the spiral faces upward, and gently stretch and twist if needed, tucking any loose ends underneath. Place each piece into a prepared muffin cup.

Repeat steps 3 through 7 with the second puff pastry sheet, using another 2 tbsp melted butter and the remaining cinnamon sugar for the filling, to make a total of 8 cruffins.

Let the filled muffin pan sit at room temperature for about 10 minutes while the oven finishes heating; the dough should relax slightly and look just a bit puffed.

Bake on the center rack for 22 to 25 minutes, or until the cruffins are well risen, deeply golden, and crisp on the edges. If tops brown too quickly, loosely tent the pan with foil for the last few minutes.

While the cruffins bake, place the remaining 2 tbsp melted butter in a small bowl. In a separate medium bowl, combine an additional 1/2 cup granulated sugar with 1 tsp cinnamon for coating, stirring in the vanilla bean paste until well distributed.

Let the baked cruffins cool in the pan for 5 minutes, then gently run a thin knife around the edges and lift them out while still warm.

Working one at a time, brush the warm cruffins lightly with melted butter, then immediately roll and turn them in the cinnamon-sugar coating until all sides are fully covered.

Serve the churro cruffins warm, or let them cool completely on a wire rack. Store leftovers in an airtight container at room temperature for up to 2 days and rewarm briefly in the oven before serving.