How to Make It
Preheat oven to 350°.
Cook pasta in boiling water for 8 minutes or until almost al dente, omitting salt and fat. Remove from heat; stir in spinach. Let stand for 2 minutes or until spinach wilts. Drain pasta mixture well.
Heat a large nonstick skillet over medium heat. Add olive oil to pan; swirl to coat. Add onion; cook 15 minutes or until golden brown, stirring frequently. Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Add flour and garlic; cook 1 minute, stirring constantly with a whisk. Gradually add milk and wine; cook 8 minutes or until sauce boils and thickens, stirring constantly. Stir in 3/4 cup cheese, salt, and rind. Remove from heat; stir in pepper. Add pasta mixture to onion mixture, and toss gently to coat.
Spoon the pasta mixture into a 13 x 9-inch glass or ceramic baking dish coated with cooking spray. Sprinkle half of panko breadcrumbs over pasta, and top evenly with remaining 1/4 cup cheese. Sprinkle the remaining half of panko breadcrumbs over cheese. Bake at 350° for 50 minutes or until browned and bubbly.