Heat olive oil in a large pot over medium heat. Add the chopped onion and sauté until softened, about 5 minutes.
- Add the minced garlic and cook for another 30 seconds until fragrant.
- Stir in the rice and cook for 2 minutes, allowing the rice to lightly toast.
- Add the chopped spinach and cook for 2-3 minutes until it wilts down.
- Pour in the vegetable broth (or water), salt, pepper, and lemon zest. Stir to combine.
- Bring the mixture to a simmer, then reduce the heat to low. Cover and cook for 15-20 minutes, or until the rice is tender and the liquid is absorbed.
- Once cooked, remove the pot from the heat and let it sit for 5 minutes before serving.
- Stir in the lemon juice and fresh dill (if using) just before serving.