2 tablespoons salted butter
2 5-ounce containers baby spinach
2 tablespoons extra-virgin olive oil, plus more to serve
2 medium shallots, halved and thinly sliced
kosher salt and ground black pepper
1½ cups long-grain white rice, rinsed and drained
1 pound extra-large (21/25 per pound) shrimp, peeled (tails removed), deveined and patted dry
1 cup lightly packed fresh dill, roughly chopped
1 teaspoon grated lemon zest, plus 3 tablespoons lemon juice
In a large saucepan over medium-high, heat the butter until it's bubbling. Add the spinach and cook, stirring, until it's wilted, but still bright green, about 1 minute. Transfer to a bowl, including any liquid released by the spinach; set aside.
Set the same pan over medium-high. Add the oil, shallots and ¼ teaspoon salt, then cook, stirring often, until the shallots are translucent, about 2 minutes.
Add the rice, 2½ cups water, and ¼ teaspoon each salt and pepper. Stir to combine, then bring to a boil. Cover, reduce to low and cook until the liquid has been absorbed, 15 to 18 minutes.
Meanwhile, season the shrimp with salt and pepper.
When the rice is done, remove the pan from the heat. Quickly and evenly scatter the shrimp over the surface, re-cover and let stand for 10 minutes.
Using a fork, fluff the rice and fold in the shrimp. Re-cover and let stand until the shrimp are opaque throughout, another 5 to 7 minutes.
Add the spinach with its liquid, the dill and the lemon zest and juice, then fold until well combined. Taste and season with salt and pepper. Serve drizzled with additional oil.