In a large skillet over medium heat, brown the ground beef until it’s no longer pink, about 5-7 minutes. Add the diced onion and cook until softened, approximately 2-3 minutes. Stir in the minced garlic cloves, followed by the marinara sauce, crumbled bacon, and season with Italian seasoning and smoked paprika. Let this simmer gently for 10 minutes.

In a saucepan, melt the unsalted butter over medium heat. Once melted, whisk in the all-purpose flour until smooth, cooking for about 1 minute. Gradually pour in the whole milk while continuously stirring, cooking until the mixture thickens, around 5 minutes. Remove from heat, and stir in the grated Parmesan cheese and garlic powder. Season with salt and pepper to taste.

Preheat your oven to 375°F (190°C). In a greased 9x13 inch baking dish, start with a layer of meat sauce. Place 4 cooked al dente lasagna noodles over the sauce, followed by a layer of the béchamel sauce and a sprinkle of shredded mozzarella and cheddar. Repeat the layering until all ingredients are used, ensuring the top layer finishes with extra mozzarella and grated Parmesan cheese.

Cover the assembled lasagna with aluminum foil and place it in the preheated oven. Bake for 30 minutes. After 30 minutes, remove the foil and continue baking for an additional 15 minutes, until the cheese is bubbling and golden brown.

Once out of the oven, let the lasagna rest for about 10 minutes before slicing. This resting period allows the layers to set, making slicing easier. Use a sharp knife to cut into squares, and serve warm, garnished with fresh parsley if desired.