Cook MANICOTTI according to package directions, less 1-2 minutes - MANICOTTI should be al dente - drain and rinse with cold water until cool. Remove to paper towels to dry. Shells are easier to stuff if cool.
*Prepare BECHAMEL Sauce*.
In a Med saucepan, melt the BUTTER over medium heat. Add the FLOUR and whisk until smooth (2 mins).
Gradually add the MILK, whisking constantly until the sauce thickens (5-10 mins). DO NOT BOIL Sauce.
Remove sauce from heat and stir in the SALT, PEPPER & NUTMEG. (Sauce can be prepared & refrigerated for up to 3 days; excellent cream sauce for any pasta dish.).
In a large bowl mix together RICOTTA, 3/4 cup PARMESAN, Egg YOLKS, BASIL, SALT & PEPPER and any OPTIONAL Ingredient.
Stuff the MANICOTTI (I use either a baby spoon or a small butter knife, stuff from both ends, don't over stuff, should have enough for at least 10-11 shells).
Reserve 1/4-1/3 Cup of the BECHAMEL Sauce, then layer the remaining BECHAMEL Sauce in the bottom of the baking dish, swirl 1/4-1/3 Cup tomato sauce into the BECHAMEL.
Lay the stuffed MANICOTTI side-by-side in dish on top of the sauce.
Top the MANICOTTI with the remaining tomato sauce, covering the pasta completely; swirl the reserved BECHAMEL Sauce on top.
Lightly cover with foil and Bake for 30 minutes; remove foil and bake for another 15 minutes.
Sprinkle with 1/4 Cup PARMESAN and bake for another 5-15 mins, until bubbly in the center and cheese is melted.