Step 1

Roll out dough on a lightly floured surface to a 20x12" rectangle, about ⅛" thick, orienting dough so that a long edge is facing you (short edges will be to your left and right). Cover dough with mortadella (overlapping the slices slightly is okay), leaving a ¼" border of dough around edges. Evenly dollop ricotta over mortadella; season with salt and pepper. Roll dough away from you, using a dough scraper if needed to peel it up and off the surface, into a tight log. Cut crosswise into 2 ½" rounds. Transfer rotolos to a parchment-lined large rimmed baking sheet, placing cut side up. Cover tightly with plastic wrap and let sit in a warm place until puffed slightly, 1–1 ½ hours.

Step 2

Meanwhile, place a rack in upper third of oven and preheat to 425°. Toast pistachios on a small rimmed baking sheet, tossing once, until fragrant and just beginning to brown, about 4 minutes. Let cool, then coarsely chop.

Step 3

Bake rotolo, rotating baking sheet halfway through, until deeply browned and dough is no longer raw in the center, 24–28 minutes.

Step 4

Meanwhile, combine garlic, oil, and pistachios in a small bowl; season with salt and pepper.

Step 5

Spoon pistachio-garlic oil over warm rotolos just before serving.