Easy Rice Bake Casserole

INGREDIENTS

• 2 tablespoons butter, plus more for dish
• Pinch cayenne pepper
• 1 small onion, minced
• 2 eggs
• 1 cup milk
• 1 teaspoon freshly chopped thyme leaves
• 4 cups cooked rice
• Salt and freshly ground black pepper
• 1 package frozen spinach, thawed, drained and chopped
• 1 teaspoon chopped basil leaves
• 1 teaspoon freshly chopped parsley leaves
• 2 cups shredded sharp Cheddar, plus extra for top