Heat oven to 350°F.
Spray a 13-inch by 9-inch baking dish with non-stick cooking spray.
Heat oil in a large skillet over medium-high heat. Add garlic and mushrooms and cook 3-4 minutes or until tender. Remove from heat.
In a small bowl, beat egg with a whisk. Add ricotta cheese and Italian seasoning. Mix well.
Spread 1/4 to 1/2 cup pasta sauce in the bottom of the baking dish. Line the bottom of the dish with a layer of noodles. Spread a thin amount of pasta sauce on the first layer of noodles. On top of noodles, layer half of the ricotta mixture, half of the cooked mushrooms, half of the remaining pasta sauce, and a layer of Cooper Sharp cheese slices. Add a new layer of noodles, then repeat layers of sauce, ricotta and mushrooms. Evenly spread the spinach. Add a final layer of noodles. Top with a thin spread of sauce and a final layer of Cooper Sharp cheese slices.
Bake for 45-50 minutes or until cheese is golden brown. Let stand 15 minutes before serving.