Set oven to 375°F. Lightly grease a 9x13-inch baking dish.
In the prepared dish, combine olive oil, chicken broth, heavy cream, paprika, garlic powder, ground mustard, peas and carrots, corn, and orzo. Add 1 cup Cheddar, 1/3 cup Parmesan, salt (I add 1 teaspoon), and pepper (I add 1 teaspoon). Stir gently until everything is well combined and press into an even layer.
Sprinkle 1/2 cup Cheddar and 1/3 cup Parmesan evenly over the top. Bake, uncovered, for 40-45 minutes, or until the orzo is tender and creamy.
Remove from the oven. Add diced chicken, broccoli, and remaining 1/2 cup Cheddar. Gently stir through then let the casserole rest, covered with foil, for 10 minutes to thicken.
Stir gently once more. Taste and adjust seasonings and serve warm.
Video
Notes
Note 1: The orzo makes a big difference. For the best results, use a high-quality Italian bronze-cut orzo made from 100% hard durum semolina. The bronze-cut method creates a rougher surface that holds sauce better and doesn’t expand as much, which keeps the pasta creamy. With high-quality orzo, bake closer to 45 minutes. With lower-quality orzo, it expands more and cooks faster, about 40 minutes.Note 2: Use a block of Parmesan and grate it on the small holes of a box grater. Lightly pack into the measuring cup for an accurate amount.Note 3: Finely dice the broccoli into very small 1/4-inch pieces, just slightly bigger than confetti. This size lets it soften quickly and blend into the orzo without turning mushy.Storage: Best eaten fresh. Store leftovers in an airtight container in the fridge for 3–4 days. Reheat gently with a splash of broth or cream to restore the creamy texture.