Pat the chicken breasts dry and drizzle them lightly with olive oil. Season both sides with garlic powder, 1 teaspoon Italian seasoning, salt, and black pepper.
Heat a few generous drizzles of olive oil in a large skillet over medium heat.
Add the chicken breasts and cook for approximately 5–6 minutes per side, depending on thickness, until browned and completely cooked through. Chicken should reach a safe internal temperature of 165°F (74°C).
Transfer the chicken to a clean plate and allow it to rest for about 10 minutes before slicing.
Reduce the heat slightly and melt the butter in the same skillet.
Add the diced onion and sauté until softened and translucent.
Stir in the minced garlic and remaining teaspoon of Italian seasoning. Cook for about 1 minute, until fragrant.
Add the dry orzo and stir it through the buttery onion mixture for approximately 2 minutes.
Pour in the chicken broth and season lightly with salt and pepper. Bring to a gentle boil.
Reduce the heat to a simmer, cover, and cook for approximately 10–12 minutes, stirring occasionally to prevent sticking, until the orzo is tender.
Uncover the skillet and stir in the baby spinach. Allow it to wilt into the hot pasta.
Reduce the heat to low. Stir in the heavy cream and freshly grated Parmesan until the sauce becomes smooth and creamy.
Add fresh lemon zest and lemon juice to taste. Stir gently until incorporated.
Arrange the sliced chicken over the Lemon Chicken Orzo and garnish with lemon slices and chopped Italian parsley.
Serve warm with additional Parmesan or lemon juice if desired.