Baked Pasta with Three Cheeses

This is also from The Williams-Sonoma Cookbook...and so good!  It makes a ton of food too!

Olive oil for coating and drizzling
1 C ricotta cheese
1 large egg yolk
1 C grated pecorino romano cheese
pinch of nutmeg
handful of coarsly chopped parsley
salt and pepper
1 pound dried pasta (small like ziti, not long like spaghetti)
1 jar of tomato sauce, heated
1/2 pound mozarella cheese, cut into small chunks

Preheat the oven to 425.
Lightly coat glass pan (9x13) with olive oil.
Boil pasta until cooked al dente.
Mix ricotta, egg yolk, 1/2 C of pecorino romano, nutmeg, and parsley in a large bowl. season with salt and pepper.
Drain cooked pasta.
Mix pasta with ricotta mixture.
Add mozarella and sauce and mix again.
Put mixture into pan.  Cover lightly with remaining percorino romano cheese and drizzle with olive oil.
Bake for 20 minutes until bubbling and lightly browned.
Serve.