Cook a starch, vegetable, and protein all in one pot! Watch Everyday Food Editor Sarah Carey make her own versatile spice rub to use in this dish.
In a medium saucepan, heat butter over medium. Add onion and garlic and cook, stirring occasionally, until onion is soft, 4 minutes. Stir in rice and poppy seeds (if using) and cook 1 minute. Stir in lemon zest and juice, broth, and zucchini and season with salt and pepper. Bring to a boil over medium-high. Reduce to a simmer, cover, and cook 13 minutes. Sprinkle spice mix over fish. Arrange fish snugly in a single layer, spice side up, on top of rice, cover, and cook until rice is tender and fish is opaque throughout, 5 to 7 minutes.