Step 1
Preheat oven to 400 degrees F (200 degrees C).
Step 2
Toss butternut squash with olive oil 1 tablespoon garlic ground sage and seasoned salt in a 9x11-inch baking dish until coated.
Step 3
Roast in the preheated oven stirring every 20 minutes until butternut squash is tender about 1 hour.
Step 4
Reduce oven temperature to 375 degrees F (190 degrees C).
Step 5
Melt butter in a large saucepan over medium heat. Add garlic; cook and stir until fragrant about 1 minute. Whisk in flour until a smooth paste forms. Slowly pour in milk; season with salt and pepper. Cook and stir sauce until thick and bubbling 8 to 10 minutes.
Step 6
Remove sauce from heat; stir in roasted butternut squash chili powder ground sage and rosemary. Puree sauce with an immersion blender until smooth.
Step 7
Mix ricotta cheese 1 1/2 cup mozzarella cheese spinach egg and Parmesan cheese together in a bowl.
Step 8
Spread 1/2 cup sauce in the bottom of the baking dish. Lay 3 lasagna noodles on top. Spread 1/3 of the ricotta cheese mixture over the noodles. Repeat layers twice more ending with remaining sauce. Sprinkle remaining 1/2 cup mozzarella cheese on top. Cover baking dish with aluminum foil.
Step 9
Bake in the preheated oven until mozzarella cheese is melted about 40 minutes. Uncover and continue baking until bubbly about 10 minutes more.