Heat a 10-inch skillet over medium heat and melt the butter for about 30 seconds to 1 minute.

Add three-quarters of the sliced scallions and the minced garlic to the skillet. Cook for about 3 minutes, stirring often, until softened.

Stir in the spinach, adding it in batches if needed, and add 1/2 teaspoon of salt. Cook, stirring occasionally, until the spinach wilts, about 5 minutes.

Pour in the stock and bring it to a simmer. Then add the orzo, lemon zest, and the remaining 1/2 teaspoon of salt.

Cover the skillet and let it simmer on medium-low heat for 10 to 14 minutes. Stir once or twice during this time, until the orzo is nearly cooked and most of the liquid is absorbed.

Next, stir in the feta cheese, peas (if using), and dill. Cover the pan and cook for another minute to finish cooking and warm the peas.

Serve by sprinkling with more feta cheese and the reserved scallions.