Prep the oven and pan: Heat the oven to 400°F (200°C). Lightly oil or spray a 9x13-inch baking dish. Spoon ½ cup marinara into the bottom and spread it evenly.

Slice the zucchini: Trim the ends. Using a mandoline or a sharp knife, slice lengthwise into thin planks, about 1/8 inch thick. Aim for long, even slices that can roll without breaking.

Draw out moisture: Lay slices on paper towels or a clean kitchen towel. Sprinkle lightly with salt and let sit 10–15 minutes. Pat dry. This step helps prevent watery roll-ups.

Optional pre-soften: Brush both sides of the zucchini with a little olive oil. Either grill or sear the slices for 1–2 minutes per side, or bake on a sheet pan for 5–7 minutes until just pliable. Don’t overcook; you want them flexible, not mushy.

Mix the filling: In a bowl, combine cottage cheese, 1 cup mozzarella, ¼ cup Parmesan, egg, basil, Italian seasoning, garlic, a pinch of red pepper flakes (if using), and a big pinch of salt and pepper. If using spinach, fold it in now. Taste and adjust seasoning.

Assemble the roll-ups: Lay a zucchini slice on your board. Spread 1–2 tablespoons of filling over it, leaving a small border at the ends. Roll gently from one short end to the other. Place seam-side down in the sauced baking dish. Repeat with remaining slices and filling. If a slice is too thin, overlap two slices slightly before filling.

Sauce and top: Spoon the remaining marinara over the roll-ups. Sprinkle with the remaining ½ cup mozzarella and ¼ cup Parmesan.

Bake: Cover loosely with foil and bake 15 minutes. Remove foil and bake another 10–12 minutes, until bubbly and lightly golden on top.

Rest and serve: Let the dish rest 5–10 minutes before serving. This helps the roll-ups set and makes them easier to plate. Garnish with extra basil and a crack of black pepper.