Preheat grill to medium. Combine tomatoes, garlic, rosemary, pepper flakes, and 1 tablespoon olive oil in a large bowl; season with salt and pepper and toss to combine. Place a large rectangle of foil on your work surface, and pour the tomatoes on top. Gather and crimp edges of foil, sealing to form a packet.
Season the eggplant with salt and pepper and brush with remaining 2 tablespoons oil. In a small bowl, stir together ricotta, parsley, and nutmeg; season with salt and pepper and set aside.
Add the foil packet and the eggplant to the grill. Grill the eggplant until charred and tender, 3 to 4 minutes per side. Grill packet, shaking occasionally, for 12 minutes.
Transfer the grilled tomatoes to a bowl and mash with a potato masher to create a sauce. To assemble, place about 1/4 cup ricotta filling on eggplant slices. Starting with a narrower side, roll the eggplant around filling. Serve stuffed eggplant with tomato sauce.
Before her diagnosis, Caroline wrote a book on cakes called Cake Magic!. She started developing a birthday cake using her gluten-free mix found in that book. Check out other recipes she’s developing for her new life—and the stories behind them—on her blog, The Wright Recipes. Her next book, Soup Club, is a collection of recipes she made for her underground soup club of vegan and grain-free soups she delivers every week to friends throughout Seattle's rainy winter. (Available February 2021.)