First, cook manicotti noodles al dente according to package directions. Drain noodles and set them on a plate or flat dish without overlapping or touching each other. This will help them from tearing or sticking together.
While noodles are cooking, begin making the sauce.
Heat olive oil in a large pot. Sauté the onion, garlic, and parsley until garlic is golden and onion is transparent.
Add the diced tomatoes, tomato sauce, basil, salt, and pepper. Bring to a simmer. Simmer uncovered for 25-30 minutes until sauce is nicely thickened.
In a mixing bowl, combine ricotta cheese, grated mozzarella cheese, Parmesan cheese, egg, dried parsley, sugar, salt, and pepper. Set aside.
When sauce is done simmering, pour half of the sauce in the bottom of a 9x13 dish.
Next, fill each al dente noodle with filling. Use a spoon to evenly distribute filling into each side of the noodle.
Place each filled noodle in the baking dish on top of the sauce.
Then, pour the remaining sauce over the noodles.
Cover dish with foil and bake at 400 degrees for 40 minutes.
Remove foil.
Sprinkle with Parmesan cheese and return to oven for 5 minutes.
Serve and Enjoy!
