In a large skillet over medium heat, heat the olive oil until shimmering. Add the chicken and season with 1 tsp of the salt and all the pepper. Spread the chicken into one layer and let cook undisturbed for 2-3 mins until golden brown, then continue cooking while stirring for 2-3 more mins until cooked through. Transfer into a bowl and set aside.
In the same pan, melt 1 Tbsp of the butter, then add the onion and cook, stirring, until softened (3-5 mins). Stir in the garlic and cook for 30 seconds.
Stir in the orzo and toast for 1 min, then add 2+½ cups of the whole milk, the chicken stock, and remaining 1+½ tsp salt. Bring to a gentle simmer, stirring often to prevent sticking.
Cook uncovered for 8-10 mins, stirring often, until the orzo is al dente and the liquid has thickened into a creamy sauce. Stir in the chopped broccoli, and cook 4-6 more mins.
Once the broccoli is tender and the orzo is creamy, stir the cooked chicken back into the pan and let it warm through for 1-2 mins.
Stir in the remaining 1 Tbsp of butter and ¼ cup of milk. Turn off the heat and stir in the lemon juice.
Serve hot, topped with freshly grated parmesan cheese and chopped fresh parsley. Enjoy!
