Tomato Jam and Mozzarella Panini

Bahan-bahan (4 porsi)

• 2 pints (about 1 ½ pounds or 4 cups) cherry tomatoes, grape tomatoes or Sungold tomatoes, halved crosswise
• 2 tablespoons honey or sugar
• 2 tablespoons apple cider vinegar
• ¼ teaspoon salt
• Several twists freshly ground black pepper
• 8 slices whole grain sourdough bread
• 2 cups grated low-moisture part-skim mozzarella (you might not need this much cheese, depending on the size of your bread)
• 1 cup grated Parmesan cheese
• Tomato jam
• 4 to 6 fresh basil leaves, torn into small pieces
• Olive oil or butter, for frying