Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and next 4 ingredients (through bay leaf) in a medium saucepan over medium heat, stirring with a whisk. Cook 8 minutes or until thick and bubbly, stirring frequently. Remove from heat; stir in salt and pepper. Spread 1 cup milk mixture in bottom of an 11 x 7-inch glass or ceramic baking dish coated with cooking spray.
Heat a large skillet over medium heat. Add 2 tablespoons water and spinach to pan; cook 2 minutes or until spinach wilts. Drain spinach, pressing until barely moist. Increase heat to medium-high. Remove casings from sausage. Add sausage to pan; cook 4 minutes or until browned, stirring to crumble. Remove sausage from pan. Add shallots and garlic to pan; sauté 2 minutes. Stir in remaining milk mixture, spinach, and cooked sausage. Remove pan from heat.
Arrange 2 noodles over milk mixture in baking dish; top with 1/2 cup ricotta and one-third spinach mixture. Repeat layers twice. Sprinkle with mozzarella and Parmesan cheese. Cover with foil coated with cooking spray. Bake at 375° for 40 minutes. Remove foil.
Preheat broiler to high.
Broil 4 minutes or until cheese is golden brown. Let stand 10 minutes.
Nice "white" lasagna, sauce is good. as with so many CL dishes, the ingredients run a little "thin". This would be better in a 9x9 pan as no boil noodles are about 3.5x7...9x9 would give more volume between the noodles. The sauce definitely needs more spice, next time I'll add some sage or thyme. I increased the sausage to 10-12 oz.
This was very good and a nice alternative to a traditional lasagna. Like others, I used enough mozzarella to cover the top; unfortunately, when I broiled it as instructed the cheese almost blackened. I think 2 minutes would have been sufficient. I did not find the prep time to be bad - I had the lasagna assembled, cooked and on the table in less than 90 minutes.
Prep time takes about a hour but that is expected when lasagna is involved. This is definitely a weekend meal but is absolutely delicious. I changed a few things up but that wouldn't change the overall outcome if you follow the recipe exactly. My family is not into spicy so I used mild turkey sausage instead of spicy. I chose to use 9 noodles to ensure it was a true layered lasagna. I also added a bit of mozzarella between each layer and chopped fresh oregano and basil to the ricotta. Also, I increased the amount of the ricotta just slightly (about 1/4 cup) so that I could cover the noodles edge to edge. Last, I added an extra ounce of mozzarella to the top for better cheesy coverage. I served with Parmesan and Pepper bread sticks (another CL recipe).
My only other comment is that next time, as other reviewers said, I'd double the recipe. It makes just an average size pan and for all the work I wouldn't mind having a second pan in the freezer for a weeknight meal.