Mediterranean Grilled Cheese with Feta, Mozzarella, and Basil

Ingredients

• 8 slices sturdy sourdough bread
• 6 oz (170 g) low-moisture mozzarella, shredded or thinly sliced
• 4 oz (115 g) feta cheese, crumbled
• 2 packed cups (60 g) baby spinach
• 1 medium Roma tomato, thinly sliced and patted dry
• 1/4 cup (35 g) Kalamata olives, chopped
• 2 tablespoons finely chopped red onion
• 1/3 cup loosely packed fresh basil leaves, torn
• 1 small garlic clove, minced
• 1/4 teaspoon dried oregano
• Freshly ground black pepper
• 3 tablespoons extra-virgin olive oil, divided