Cook pasta according to a large pot, reserving 1 cup of pasta water.
Place the spinach in the colander. Drain the pasta into the colander, wilting the spinach.
Preheat your oven to 350F.
In a bowl, mix ricotta, egg, Parmesan cheese, black pepper and salt until well combined. Stir in the reserved pasta water.
In a large skillet, add butter, olive oil and garlic. Cook on low for about 5 minutes.
Stir in the ricotta/egg mixture.
Add the cooked pasta/spinach mix into the ricotta sauce and 1 cup of the mozzarella cheese.
Add the pasta mixture to a 2-2 1/2 quart (or 9x13-inch baking dish). Sprinkle with remaining cheese.
Bake for 15-20 minutes or until cheese is melted.