Fresh veggies layer between ricotta, mozzarella, and Parm in these single-serving lasagnas, perfect for vegetarians and cheese-lovers alike.
Preheat the oven to 350°.
In a large pot of boiling salted water, cook the lasagna noodles until al dente. Drain the noodles and let them cool while you make the filling.
In a large skillet, heat the oil over medium-high. Add the onion and cook, stirring often, until light golden,5 minutes. Add the zucchini, yellow squash, oregano, and crushed red pepper, if using. Season with salt and pepper. Cook, stirring often, until the squash softens and is beginning to brown slightly, about 12 minutes. Stir in the tomatoes with juices, lower the heat to medium, and simmer until the sauce reduces slightly, 10 to 15 minutes.
In a medium bowl, stir together the ricotta, 2 cups mozzarella, 1 cup Parmesan, and the egg; season.
Using a small ramekin (10 oz.) as a guide, cut the lasagna sheets into rectangles about 4 inches wide. Put a heaping 1/4 cup of sauce in the bottom of one ramekin. Add one or two lasagna sheets to cover the bottom (slightly overlapping is OK), then add about 1/4 cup of the cheese mixture, spreading the cheese to cover the noodles. Top with 1/4 cup sauce, spreading to coat. Repeat once with the remaining noodles, cheese mixture, and sauce. (You should be able to fill 6 ramekins.) Sprinkle some mozzarella and Parmesan on top of each lasagna.
Bake until golden brown on the top, 35 to 40 minutes. Let stand for 5 minutes before serving.