How to Make It
In a medium bowl, whisk the flour with the salt. In a small bowl, whisk the eggs with the milk. Whisk the egg mixture into the flour mixture until smooth. Whisk in the melted butter until just blended. Cover the batter and refrigerate for 1 hour.
Heat a 10-inch nonstick skillet over moderately high heat. With a paper towel, rub the skillet with olive oil. Pour in 1/4 cup of the crespelle batter and tilt the skillet to distribute the batter. Cook the crespella until golden brown on the bottom, 2 minutes. Flip and cook until browned in spots, 1 minute longer. Invert the crespella onto a baking sheet. Repeat with the remaining batter, rubbing the pan with oil as needed. You should have 8 crespelle.
Preheat the oven to 375°. In a medium bowl, blend the ricotta with the chopped parsley and 1/3 cup of the Parmigiano-Reggiano cheese. Season the filling with salt and pepper.
Lay the 8 crespelle on a work surface. Spread 2 rounded tablespoons of the ricotta filling over half of each crespella. Fold the crespelle over the filling, then fold them in half again to form quarters.
Spread half of the marinara sauce in the bottom of a 9-by-13-inch baking dish. Arrange the filled crespelle in the dish in a single layer, overlapping them slightly. Top with the remaining marinara sauce and sprinkle with the remaining 1/3 cup of Parmigiano-Reggiano cheese. Bake for about 25 minutes, until golden brown and bubbling; serve.