Preheat Oven:
Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish with butter or non-stick spray.
Cook Lasagna Noodles (if needed):
If using traditional lasagna noodles, cook them according to package instructions. Drain and set aside.
Prepare the Bechamel Sauce:
In a medium saucepan, melt the butter over medium heat. Whisk in the flour and cook for 1-2 minutes until slightly golden.
Gradually whisk in the milk and cream. Continue whisking until the sauce thickens, about 3-5 minutes.
Stir in garlic powder, onion powder, nutmeg (if using), and season with salt and pepper. Remove from heat.
Assemble the Lasagna Layers:
Spread a thin layer of the bechamel sauce on the bottom of the baking dish.
Lay down 3 lasagna noodles. Top with a layer of diced ham, a dollop of ricotta cheese (spread lightly), shredded Gruyere, and mozzarella. Pour some bechamel sauce over the layer.
Repeat the layering process two more times, ending with a final layer of bechamel and cheese on top.
Make the Egg Custard:
