For the pasta frolla, combine the dry ingredients and mix well. Rub in the butter until it is absorbed, making sure the mixture remains cool and powdery and does not become pasty. Beat the egg with the milk or water and stir in with a fork. Continue stirring until the dough holds together, then briefly knead it, just until smooth. Shape into a disk, wrap in plastic, and refrigerate at least 1 hour, or until firm.
For the filling, press the ricotta through a fine sieve or strainer into a bowl. Beat together the ricotta, eggs, salt, and pepper. Beat in the grated cheese.
Spread one-third of the filling on the dough in the bottom of the pan. Strew with half of the mozzarella and half the sausage. Cover with another third of the filling. Strew with the remaining mozzarella and sausage. Spread with the remaining filling.
Roll out the reserved dough into a
Bake at 350 degrees for about 45 minutes, until the filling is set and the pastry is a light gold. Cool in the pan before unmolding. To unmold, invert onto a flat plate, lift off the pan, replace the pan with another plate or platter, then reinvert so that the pizza is right side up. Serve the pizza at room temperature.
© 1990 Nick Malgieri. All rights reserved.