To make the batter:

1. Mix flour, eggs, salt,and milk in a blender until smooth. Cover and refrigerate for at least 30 minutes.

To Make the filling:

1. Combine the ricotta, mozzarella, pecorino, salami, and nutmeg in a medium bowl. Stir with spatula until smooth and fully combined.
2. Heat a crepe pan or skillet over medium-high heat until hot. (If you're new to crepe-making, I would recommend using a lower temperature at first until you get the hang of it.) Brush pan with olive oil, reduce the heat to medium, and pour a few tablespoons of batter into the pan, swirling to coat the bottom of the pan evenly with the batter. Cook until lightly golden, about 30-40 seconds.
3. Flip crepe over gently and cook the other side for about 20-30 seconds.
4. Continue making crepes until all the batter has been used. You should have 12-15 crepes.
5. Preheat the oven to 450 degrees F. Butter a 9x13-inch baking dish with some of the butter.
6. Set aside 1/4 cup of the filling mixture for the topping. Fill each crepe with 3 or 4 tablespoons of the filling and carefully fold the crepe in half.
7. Arrange the crepes, overlapping slightly, in the baking dish.Spread the reserved filling over the top and dot with the remaining butter.
8. Bake 12 to 15 minutes until very hot and crisp on top. Serve hot.
9.