Layer some of the marinara sauce on the bottom of a baking pan.
Gently place a layer of the ravioli on top of the sauce.
Pour another layer of marinara sauce on top of the ravioli.
Pour the ricotta/egg/cheese mixture over the marinara sauce.
Gently place a second layer of the ravioli on top of the cheese mixture.
Pour the last of the sauce on top of the ravioli.
Place all of the mozzarella slices on top; use finely grated mozzarella cheese if you don't have the soft balls.
Bake in a preheated 350 F oven for 45 minutes on the lowest rack of the oven.
Half-way through the baking, check to see if the cheese is getting too dark.
If so place a baking sheet above the ravioli bake on the oven rack above OR lightly cover with aluminum foil; you don't want the cheese to burn.