Season the chicken: Pat the chicken dry and season with 1/2 teaspoon salt, 1/4 teaspoon black pepper, the Italian seasoning, and smoked paprika if using. Toss to coat.
Sear the chicken: Heat the olive oil and 1 tablespoon butter in a large deep skillet over medium-high heat.
Add the chicken in a single layer and cook until lightly browned and just cooked through, 4–6 minutes. Transfer to a plate and cover loosely.
Sauté aromatics: Reduce heat to medium. Add the remaining 1 tablespoon butter to the same pan.
Stir in the onion with a pinch of salt and cook until softened, 3–4 minutes. Add the garlic and cook 30 seconds, until fragrant.
Toast the orzo: Add the dry orzo to the pan and stir for 1–2 minutes. Light toasting deepens its flavor and helps it hold texture.
Add liquids and simmer: Pour in the chicken broth and milk (or cream).
Stir well, scraping up any browned bits. Bring to a gentle simmer.
Cook the orzo: Reduce heat to medium-low and cook uncovered, stirring often so it doesn’t stick, 8–10 minutes. The mixture should bubble gently.
If it gets too thick before the orzo is tender, add a splash of broth.
Add broccoli: Stir in the broccoli and cook 3–4 minutes more, until bright green and crisp-tender. If using frozen broccoli, add it a minute earlier.
Finish with chicken and cheese: Return the chicken and any juices to the pan. Stir in the Parmesan until melted and creamy.
Add red pepper flakes if you like a little kick.
Adjust and brighten: Taste and season with more salt and pepper as needed. Stir in the lemon juice to lift the flavors. The sauce should be creamy and slightly loose—it will thicken as it rests.
Serve: Let it sit 2 minutes off heat.
Garnish with parsley and extra Parmesan. Serve warm.