Bring a large pot of salted water to a rolling boil. Add the orzo pasta and cook according to package instructions until al dente, about 8-10 minutes. Drain and set aside.

In a large cast-iron skillet, heat 2 tablespoons of olive oil over medium heat. Add the minced garlic and diced onion, sautéing for 2-3 minutes until the onion is translucent.

Whisk in 1 tablespoon of all-purpose flour, stirring constantly for about 1 minute until lightly browned.

Gradually pour in 1 cup of whole milk, whisking continuously until smooth. Keep stirring for about 3-4 minutes until thickened.

Add 3 cups of baby spinach, stirring until wilted and vibrant.

Stir in 1 cup of grated Parmesan cheese until melted. Fold in the cooked orzo, seasoning with kosher salt and freshly ground black pepper to taste.