In a mixing bowl, combine flour and salt. Make a well in the center and add eggs and olive oil. Mix until dough forms.
Knead the dough on a floured surface for about 10 minutes. Wrap in plastic wrap and let rest for 30 minutes.
In another bowl, mix all the cheeses for the filling.
Roll out the dough thinly and cut into squares. Place a teaspoon of filling on each square, brush edges with beaten egg, and cover with another square. Seal edges with a fork.
Boil ravioli in salted water for 3-4 minutes or until they float. Serve with your favorite sauce.