Vegetarian Couscous Casserole

• 5 ingredients
• 2 baking dish coated with cooking spray
• 475 gr black beans (canned)
• 350 ml water
• 230 ml water (canned sliced)
• 190 gr spinach leaves (fresh)
• 160 gr couscous
• 140 gr no salt added (whole)
• 120 gr skim ricotta cheese
• 50 gr green onions (minced)