Overnight Ham and Gruyère Breakfast Lasagna

Spray 13x9-inch (3-quart) glass baking dish with cooking spray.

In 4-quart saucepan, melt butter over low heat. With whisk, stir in flour until smooth. Increase heat to medium; cook and stir until mixture is smooth and bubbly. Gradually stir in milk. Increase heat to medium-high; heat to boiling, stirring constantly. Boil and stir 1 minute; reduce heat to medium. Stir in Gruyère cheese. Cook until melted, stirring occasionally. Remove from heat; cool 5 minutes.

Assemble lasagna starting with 3/4 cup of cheese sauce in bottom of baking dish. Layer 3 noodles, 2/3 cup of the ham, 1 cup of the spinach, 1/2 cup of the mozzarella cheese, and top with 3/4 cup of the cheese sauce. Repeat layers 2 more times starting with noodles. Top with remaining 3 noodles and remaining 3/4 cup of cheese sauce.

Meanwhile, in 4-cup glass measuring cup, beat eggs, Dijon mustard, salt and pepper. Carefully pour egg mixture over assembled lasagna. Cover and refrigerate at least 3 hours but no longer than 12 hours.

Heat oven to 350°F. Uncover and bake 50 to 55 minutes or until top is lightly browned, center is set and knife inserted in center comes out clean. Let stand 5 minutes. Top with fresh thyme.