01 - Heat olive oil in a large, deep skillet or sauté pan over medium heat. Add the chopped onion and cook for 3 to 4 minutes until softened and translucent. Stir in the minced garlic and cook for another 30 seconds until fragrant.
02 - Add the orzo pasta to the pan and toast for 1 minute, stirring continuously to coat each grain in the olive oil mixture.
03 - Pour in the vegetable broth along with the lemon zest and half of the lemon juice. Stir well to combine, bring to a gentle simmer, then reduce the heat to low.
04 - Cover the pan and cook for 10 to 12 minutes, stirring occasionally, until the orzo is tender yet still has a slight bite and most of the liquid has been absorbed.
05 - Uncover the pan and fold in the fresh baby spinach. Cook for 1 to 2 minutes, gently tossing until the leaves are wilted and vibrant green.
06 - Remove from heat and stir in the crumbled feta cheese, remaining lemon juice, crushed red pepper flakes, salt, and freshly ground black pepper. Sprinkle with chopped fresh dill or parsley. Serve immediately, garnished with additional feta or herbs if desired.