Combine spaghetti sauce, tomatoes and liquid. Stir to break up tomatoes. Combine Ricotta cheese, 1/2 cup Mozzarella, egg and garlic powder. Mix well.
Spread 1/3 spaghetti sauce mixture in bottom of microwave dish (7"x11"). Place 3 noodles on top of sauce. Spread one half ricotta mixture over noodles. Layer 1/2 of spinach and 1 cup Mozzarella on top. Repeat layers (sauce, noodles, Ricotta, spinach and Mozzarella). Cover with remaining noodles. Pour remaining sauce over top. Cover with microwave plastic wrap. Turn back one corner to vent. Cook at full power 8 minutes. Give 1/2 turn. Cook at 50% power for 30 to 35 minutes. Give 1/2 turn after 15 minutes. Let stand 10 minutes before cutting.
