Bring about 8-10 cups water to a full boil – you can salt the water if you’d like – and add the manicotti shells. Only cook for 4-5 minutes to slightly soften the shells, but NOT cook them fully. We want them harder than al dente. When they are done, drain and run under cold water to stop the cooking. Set aside.
Meanwhile, in a frying pan, heat the oil and saute the diced peppers, green onion, and garlic just until tender (about 3-4 minutes). Remove from heat and set aside. This part smells AMAZING! Don’t be tempted to sneak a taste – not yet!
In a large bowl, Mix the three cheeses and the beaten egg.
Once the pepper/onion mixture has cooled, add them to the cheese mixture and stir well.
In a separate bowl, mix the pasta sauce with the 1 cup of water. Set aside.
Take out a 9X13 baking dish and pour half of the sauce/water mixture in the bottom.
Now you are going to stuff the manicotti shells with the cheese/pepper mixture. Fill using a small spoon or however you can manage it! I usually hold the nooodle in one hand and kind of squeeze it so the opening is wide, and use a small spoon to drop the filling in. You could try using an icing bag, but I find this filling kind of chunky so it doesn’t usually work well.
Lay the stuffed manicoti shells over the sauce layer in the baking pan, and pour the rest of the sauce over the top, making sure to cover all of the noodles evenly.
Cover the pan with foil and bake for about 45 minutes or until the insides of the manicotti is bubbly hot and the noodles are softened.