Heat the olive oil in a large 12-inch skillet over medium-high heat. Add the sliced chicken sausage and cook for 3 to 4 minutes until the edges develop a caramelized brown color with some darker spots. Remove the sausage from the pan and set it aside on a plate.

In the same skillet, add the chopped onion and minced garlic. Sauté for about 2 minutes until the onion softens and becomes translucent.

Add the orzo to the skillet and toast it for 1 to 2 minutes, stirring frequently. Pour in the chicken broth and bring everything to a boil, then reduce the heat to medium-low.

Let the orzo simmer for 7 minutes, stirring occasionally to prevent sticking. When you have exactly 3 minutes of cooking time remaining (at the 7-minute mark), stir in the broccoli florets and cover the pan. The steam will soften the broccoli while the orzo finishes absorbing the broth.

Return the browned sausage to the skillet. Add the lemon juice and Parmesan cheese if using. Mix everything together until well combined and slightly creamy. If the mixture looks too dry, add a splash of extra broth. Season with salt and pepper to taste, then serve hot.