Chop the onion and garlic. Cut the broccoli into bite-sized florets. Grate the cheddar cheese.

In a medium saucepan, bring the chicken broth to a boil. Add the orzo pasta, reduce heat to low, cover, and simmer for 8-10 minutes, or until the orzo is cooked through and the liquid is absorbed. Stir occasionally to prevent sticking.

While the orzo is cooking, melt the butter in a large skillet over medium heat. Add the chopped onion and cook until softened, about 3-5 minutes. Add the garlic and cook for another minute, until fragrant.

Sprinkle the flour over the onion and garlic mixture and cook for 1 minute, stirring constantly. Gradually whisk in the milk until smooth. Bring to a simmer, stirring constantly, until the sauce thickens slightly.

Add the broccoli florets to the skillet with the cheese sauce. Cook for 5-7 minutes, or until the broccoli is tender-crisp.

Remove the skillet from the heat. Stir in the grated cheddar cheese until melted and smooth. Add the cooked orzo to the skillet and stir until everything is well combined. Season with salt and pepper to taste. Add a pinch of nutmeg if desired.

Serve immediately. Garnish with extra cheese, a sprinkle of red pepper flakes, or some chopped fresh parsley, if desired.