Baked Spinach and Artichoke Toasts
1 (10 ounce) package frozen chopped spinach -… 1 (8 ounce) package cream cheese, at room tem… 1 loaf French bread 1 pinch cayenne pepper 1 pinch freshly grated nutmeg 2 cups chopped marinated artichoke hearts 3 cloves garlic, finely minced freshly ground black pepper to taste ¼ cup finely grated Parmigiano-Reggiano chees… ¼ cup unsalted butter, melted ½ cup grated Gruyere cheese ½ cup grated provolone cheese ½ teaspoon salt, or to taste ⅓ cup thinly sliced green onion, white and li…