Enjoy a quick and nourishing meal with tender cod fillets served over spinach and draped in a vibrant caper-orange sauce that's briny, sweet, and gently spiced, perfect for any weeknight dinner.

8 cups/11 ounces packed spinach leaves, stemmed and roughly torn if large, or use baby kale or chopped stemmed collard greens 4 (5- to 7-ounce) skinless cod fillets (or other white fish such as ...