Prosciutto Renyah, Sage Pesto, dan Keju Panggang Tomat

Bahan-bahan (2 porsi)

• 1 tomato, thinly sliced
• kosher salt and black pepper
• 3 ounces prosciutto
• 4 slices sourdough bread
• 1 cup shredded fontina
• 1/2 cup shredded mozzarella
• 1/4 cup basil pesto
• 2 tablespoons chopped fresh sage
• 1 cup fresh baby arugula
• 4 tablespoons salted butter, at room temperature
• 2 tablespoons grated parmesan cheese