Whisk eggs, milk, salt and pepper together in a small bowl.
Heat a 6 inch nonstick skillet with cooking spray.
Pour 3 tablespoons of egg mixture in the skillet, swirl around, cook until set about 1 minute.
Carefully slide it off the skillet onto waxed or parchment paper to cool.
Follow same procedure until no more batter is left.
To assemble crepes: Add 3-4 cubes of fontina, 3-4 cubes of mozzarella, cover with spinach and fold sides over. Lay seem side down in baking dish. Top crepes with marinara sauce, Parmesan cheese and bake 15 minutes.