To make the batter, in a medium mixing bowl, whisk the eggs and milk. Once eggs and milk are well combined, whisk in flour until smooth - set aside and rest for 30-45 minutes.
Heat a nonstick crepe pan over medium-high heat. Lightly brush it with vegetable oil and return to heat. Pour a little less than ½ cup of batter into the pan, swirling to cover the bottom of the pan evenly. Cook for about 30 seconds or until it has set and the bottom is lightly browned. Turn the crepe over carefully with a spatula or fork. Cook for an additional 15 seconds or until set. Remove from pan and place on a piece of wax paper. Continue cooking and stacking crepes until you have at least 14. The extra 2 will allow for breakage.
Using a wooden spoon, combine ricotta, egg yolks, diced mozzarella, Pecorino Romano cheese, salt and pepper until well blended.
Preheat oven to 375* F.
Lay crepes out in a single layer. Place a heaping tablespoon of the ricotta mixture in the center at top of the crepe, spreading out to the edges. Fold the ricotta covered portion over onto the crepe. Fold the edges in and roll into a firm packet.
Spread Rao's Homemade® Marinara Sauce over the bottom of a 13 x 9 x 2 baking pan. Lay rolled crepes on top of the Marinara Sauce. Place a slice of mozzarella on top of each rolled crepe.
Bake manicotti in preheated oven for approximately 12 minutes or until filling is hot and cheese has melted. Serve, allowing 2 pieces per person.