Step 1

Preheat the oven to 425° F (convection roast if you have it). Line two standard sheet pans or one x-large sheet pan with parchment paper or Silpats, or rub lightly with olive oil. Trim the stem end of each zucchini. Stand each vertically, and make 1/4-inch thick cuts down to create long slices—these don’t have to be perfect. Arrange the slices on the prepared sheetpans. Drizzle the zucchini with the olive oil. Season with salt and pepper. Transfer the pan to the oven and roast for 15 minutes to 20 minutes.  Note: The cooking times will vary depending on how thinly you slice your zucchini—if you slice them less than 1/4-inch thick, you won’t need the full amount of cooking time. Know that the timing is forgiving, however—you just need the zucchini to be pliable so that they can roll into a coil. If you cook them too much at this step, they’ll become brittle and won’t roll properly.

Step 2

Remove the pan from oven. Keep oven on.

Step 3

Meanwhile, if you are adding the Swiss chard, in a large sauté pan set over high heat, heat the tablespoon of oil until shimmering. Add the chard leaves, season with a pinch of salt and pepper, and sauté, rearranging with tongs as necessary. Cook the chard for about 2 minutes or until wilted. Remove pan from heat.

Step 4

To make the filling, in a medium bowl, stir together the ricotta, lemon zest, thyme, if using, and 1/4 teaspoon salt. When chard has cooled briefly, stir it into the ricotta mixture. Taste mixture. Add more salt to taste—I always add more salt … this is your chance to make sure the filling is seasoned properly.

Step 5

Spoon tomato sauce into two 9-inch round baking dishes or one 12-inch round baking dish or one 9×13-inch baking dish—the bottom of the dish should be covered in a thin layer. Place a spoonful (about 2 teaspoons) of filling at one end of each of the zucchini slices. Roll the slice into a tight coil and place it seam-side down in the dish on top of the tomato sauce. Drizzle lightly with olive oil. Season lightly with salt and pepper. Transfer to the oven and bake until the sauce has reduced slightly and is bubbling, and the rolls are lightly golden on top, 20 to 25 minutes. If the rolls are still not golden after the 25 minutes, remove the pan from the oven and preheat the broiler. Broil the involtini for about 3 minutes keeping a close watch the entire time.

Step 6

Remove pan from the oven and shave Parmesan over top if using. I like using my microplane for this.

Step 7

Note: If you have extra ricotta filling, store it in the fridge. It’s delicious spread over grilled bread.