Codfish with spinach, carrots and chickpeas au gratin - Riberalves

Ingredients

• Olive oil q.s.
• 1 large onion
• 1 clove of garlic
• 2 medium carrots
• 300 g baby spinach leaves
• 400g of cooked chickpeas
• Salt and black pepper q.s.
• 500 ml of béchamel sauce
• Butter q.s.
• 150 g of grated mozzarella cheese