Cheesy Spinach Stuffed Shells (Baked & Bubbly)

Ingredients

• 1 (10 oz / 280 g) package frozen chopped spinach, thawed and squeezed dry
• 15 oz (425 g) whole milk ricotta cheese
• 1 cup (100 g) freshly grated parmesan cheese
• 1 large egg
• 3 cloves garlic, minced
• 1/2 teaspoon Italian seasoning
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 18-20 jumbo pasta shells (conchiglioni)
• 24 oz (680 g) marinara sauce
• 1 1/2 cups (170 g) shredded low-moisture mozzarella
• 2 tablespoons olive oil
• Fresh basil, for garnish (optional)