Use the 1 tablespoon of butter to thoroughly coat the bottom and insides of a 9-inch (23 cm) springform pan. Dust pan with 1/2 cup (50 g) of Parmigiano cheese all over.

Melt the remaining 1/4 cup (58 g) of butter in a medium sized pot over medium heat. Whisk in flour to make a roux and cook for about 2 minutes to remove raw taste, then slowly whisk in milk. Bring to a simmer, whisking often, and cook for about 10 minutes or until white sauce has thickened and shows whisk marks. Still over heat add grated Havarti and 1 cup (100 g) Parmigiano and whisk until melted and smooth. Whisk in egg and season with salt and pepper. Remove from heat and keep warm.

Position rack in center of oven. Preheat oven to 375°F/190°

Bring a large pot with 5 quarts (4.7 L) of salted water to a boil and cook pasta until al dente; drain and transfer to a large mixing bowl. Add warm cheese sauce, baby spinach or arugula and 1/4 cup (8 g) parsley to pasta and stir to combine. Stir in cottage cheese, feta and tomatoes. Pack mixture into prepared pan. Sprinkle reserved 1/2 cup (50 g) Parmigiano evenly on top.

Bake pasta for about 30 to 35 minutes or until top is golden brown and a bit crispy. Let rest at least 20 minutes before unmolding. Sprinkle with reserved 1/4 cup (8 g) parsley, cut into wedges and serve. Pasta may be served warm or at room temperature. Refrigerate leftovers well wrapped in plastic wrap and reheat in microwave, if desired.