In a large pot, heat the olive oil over medium heat. Add the diced onion, sliced leek, and chopped garlic. Sauté for a few minutes until they are soft and fragrant.
Add the washed rice to the pot along with the salt and pepper. Stir well to combine, toasting the rice slightly for about a minute to enhance its flavour.
Pour in the water, then gradually add the spinach, stirring continuously until it wilts. Bring the mixture to a boil, then reduce the heat to a simmer and cover the pot with a lid.
Let the spanakorizo simmer for about 20 minutes or until the rice is fully cooked and the liquid is absorbed. Check occasionally to ensure it doesn’t dry out, adding more water if needed.
Once the rice is tender, stir in the chopped dill, chopped mint, lemon zest, and lemon juice. Mix well to evenly distribute the flavours, then turn off the heat.
Drizzle with additional olive oil to taste. Adjust the seasoning with more salt and pepper if needed. Cover and let the dish rest for 10 minutes to allow the flavours to meld.
Serve with a sprinkle of crumbled Greek feta cheese on top (optional), and enjoy!