On a baking sheet lined with paper towels, arrange zucchini strips in a single layer; season with salt. Let sit 15 minutes to let zucchini release moisture, then blot dry with more paper towels (zucchini should be dry to the touch).

Spray a standard (12-cup) muffin tin with cooking spray. On a clean work surface, roll out one sheet of puff pastry to a 10” x 9” rectangle (if pastry is cold, you shouldn’t need flour). Using a pastry cutter or a sharp knife, slice rectangle horizontally into 6 strips about 1 ½” wide and 10” long.

Spread one strip with about 2 teaspoons pesto, then line with zucchini strips, trimming and dividing strips as needed to fit length of pastry. Sprinkle zucchini with 1 tablespoon mozzarella, then roll strip into a tight coil. (If you like, you can slightly coil one long side of the strip as you roll it up to encourage it to take on a budding rose shape.) Arrange in prepared tin cut side up. Repeat with remaining strips, then repeat process with remaining sheet of puff pastry.

Refrigerate roses in tin until cold, 20 to 30 minutes.

Preheat oven to 400°. Bake roses until crisp and deeply golden brown all over, 25 to 30 minutes. (Some oil will have leaked into bottom of tins, and that’s okay!) Let cool in tin 5 minutes, then carefully remove with an offset spatula or butter knife. Transfer to a platter and serve warm.