Kosher salt
1 head escarole, coarsely chopped
1 head garlic, cloves separated but not peeled
6 tablespoons butter
10 to 12 fresh sage leaves, torn
1 pound butternut squash, peeled and cut into bite-size pieces
Freshly ground pepper
1 1/2 cups chicken stock
3 tablespoons all-purpose flour
3 cups milk
Freshly grated nutmeg
Two 15-ounce cans pure pumpkin puree
3 eggs
2 cups fresh ricotta
2 cups freshly grated Parmigiano-Reggiano
1 box no-boil flat lasagna
12 ounces Italian Fontina, Fontina Val D'Aosta or Gouda cheese, shredded