Heat 1 tbsp olive oil in a large skillet over medium heat.
Add the chopped onion and sauté for 2 minutes until softened.
Stir in the garlic and cook for 30 seconds until fragrant.
Add the orzo pasta to the skillet and stir to coat in the oil and aromatics.
Cook for 1-2 minutes, stirring often, to lightly toast the orzo.
Pour in the broth, stirring to combine.
Bring to a simmer, then reduce heat to low.
Cover and cook for 10-12 minutes, stirring occasionally, until the orzo is tender and most of the liquid is absorbed.
Stir in the chopped spinach, letting it wilt for 1-2 minutes.
Remove from heat and add the feta cheese, lemon juice, and lemon zest.
Stir gently to combine.
Taste and adjust seasoning with salt and black pepper if needed.
Serve warm and enjoy as a main dish or a side.