Fish with fennel and citrus is a classic combination. This dish (which uses only one pan!) features grapefruit, a slight variation from the lemon that’s more commonly used. My father used to eat grapefruit for breakfast every morning, and I still remember the first time he gave me a bite to taste. The shockingly bright citrus was almost as transformative as my first steamed clam. Be it nostalgia or otherwise, it’s been one of my favorite fruits ever since. I adore the trout I buy from my local seafood market, but I know it can be hard to find. Cod, salmon, sea bass, or even scallops work well as a substitute.