Preheat oven to 350º.
Lightly spoon flour into a dry measuring cup; level with a knife. Place a large saucepan over medium heat; add flour to pan. Gradually add milk to pan, stirring constantly with a whisk until smooth; cook 1 minute. Stir in butter, thyme, salt, and pepper; bring to a boil. Cook 5 minutes or until thick, stirring constantly. Remove pan from heat; stir in 1 1/4 cups Parmigiano and nutmeg. Set cheese sauce aside.
Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add onion; sauté 4 minutes. Add garlic; sauté for 1 minute. Remove from heat. Add cream cheese; stir until cheese melts. Stir in half-and-half, 1/4 cup parsley, shrimp, and scallops. Combine eggs and ricotta in a food processor; process until smooth. Stir ricotta mixture into seafood mixture.
Spoon 1 cup cheese sauce into bottom of a 13 x 9-inch baking dish coated with cooking spray. Arrange 4 noodles over sauce; top with half of ricotta mixture. Repeat layers with 4 noodles, remaining half of ricotta mixture, and remaining 4 noodles. Pour remaining cheese sauce over noodles; sprinkle with remaining 3/4 cup Parmigiano. Bake at 350° for 45 minutes or until lightly browned. Sprinkle lasagna with remaining 1/4 cup parsley. Let stand 10 minutes before serving.
Wine note: The rich, mellow flavor and creamy, mouth-filling texture of this seafood lasagna demands a white wine that's soft and full on the palate. Chardonnay is a great answer-especially a luscious, full-bodied Italian version like Antinori's Cervaro della Sala 2003 from Umbria ($45). -Karen MacNeil