1. Prepare Tomato-Cheese sauce; cover with foil, and keep warm.
2. Preheat oven to 350 °. Melt butter in a large nonstick skillet over medium-high heat. Add onion, and cook 5 minutes or until translucent, stirring occasionally. Stir in garlic, and cook 2 minutes. Add spinach, and cook 1 minute. Remove skillet from heat, and stir in cream and shrimp. In a separate bowl, whisk together ricotta cheese, eggs, and salt. Stir ricotta mixture into shrimp mixture.
3. Spread 1 cup Tomato-Cheese Sauce in bottom of a greased 13- x 9-inch baking dish. Arrange 4 noodles over sauce; top with half of shrimp mixture. Place 4 more noodles over shrimp mixture, and top evenly with 3/4 cup sauce. Top with remaining shrimp mixture and noodles. Spread remaining sauce over lasagna, and sprinkle with Parmesan cheese. Bake 40 to 45 minutes or until lightly browned. Remove from oven, and let stand 15 minutes before serving.