Step 1

For the dough:

Step 2

Place flour, food processor blade and a mixing bowl in the freezer for 20 minutes.

Step 3

Assemble food processor and add flour, shortening and butter. Pulse until the mixture resembles tiny pebbles. Add the vinegar and pulse again. Add the water 1 tablespoon at a time until the dough just comes together (you may not need all the water).

Step 4

Transfer the dough to a lightly floured surface. Working quickly, roll the dough into a 10- by 16-inch rectangle.

Step 5

Fold the long ends of the dough toward the center, then fold in half from left to right, bringing the short ends together. With the smooth end on your left, roll the dough again into a 10- by 16-inch rectangle and repeat the fold. Turn the dough and repeat the roll and fold for a third time.

Step 6

Place the dough on a parchment paper–lined sheet tray and set in the freezer for 30 minutes.

Step 7

For the filling:

Step 8

While dough chills, stir together all filling ingredients in a small bowl.

Step 9

To assemble:

Step 10

Whisk together the egg and milk in a small bowl to make an egg wash.

Step 11

Heat the oven to 375 F.

Step 12

On a very lightly floured work surface, reroll the dough into a 10- by 16-inch rectangle (it should be about 1/4-inch thick) if it has shrunk.

Step 13

Sprinkle evenly with the filling mixture and press the mixture gently into the dough to adhere.

Step 14

Starting with one of the long ends, roll the dough into a tight spiral and pinch the ends to seal them closed. (If the dough starts to feel warm or sticky, refrigerate it for 15 minutes — it's important to keep the fat as cold as possible!)

Step 15

Place the roll on the lined sheet tray with the seam side down. Brush all over with the egg wash and bake for 45 to 50 minutes, until golden brown.

Step 16

Remove from oven and immediately dust with remaining coconut sugar.

Step 17

Let cool for 20 to 25 minutes, until cool enough to handle, then slice diagonally into 1½-inch pieces. It's best to do this right on the sheet tray, as the roll is flaky and delicate.

Step 18

Place the slices swirl-side up and bake for 5 to 10 minutes more, until the swirls appear dry. Let cool completely before serving.