Pre-heat the oven to 350ºF.

Heat a large pot of salted water to a boil. Add the pasta and cook until it is al dente, according to the package directions. Drain the pasta and set it aside (no need to rinse).

Melt 1 tablespoon of butter in a large sauté pan. Add the spinach and sauté for 2 minutes, until the spinach has wilted and much of the liquid has evaporated. Add the artichokes, garlic and season with salt. Sauté for another minute or two. Remove the spinach and artichokes and rough chop. Set aside.

Add the remaining butter to the sauté pan and heat over medium heat. Add the flour and cook for 2 minutes. Stir in the room temperature milk. Stirring regularly, bring the sauce to a boil. Once it has boiled and thickened, remove the pan from the heat and stir in the cheeses and lemon zest. Season with salt and freshly ground black pepper.

Stir in the spinach and artichokes and then add the cooked pasta. Stir very well to combine.

Combine the tablespoon of melted butter and the breadcrumbs in a small bowl and sprinkle the mixture on top of the pasta. Transfer the sauté pan to the oven and bake at 350ºF for 30 minutes, until lightly browned on top and bubbling around the side.