Preheat oven to 350 degrees. Grease a 9×13 baking dish with nonstick spray.
Cook quinoa according to package instructions.
Meanwhile heat 1 tablespoon oil in a large skillet. Add panko and cook stirring constantly until golden brown. Add a sprinkle of salt. Remove from the pan and set aside.
In the same pan heat the remaining tablespoon of oil. Add the broccoli and cook until tender.Season with salt and pepper and set aside.
To make the cheese sauce start by melting butter in a medium saucepan. Add in flour and whisk constantly for about 1 minute.
Slowly add in milk, mustard powder, onion powder, garlic powder and Italian seasoning. Continue to whisk until thickened slightly, 3-4 minutes.
Take off of the heat and stir in 1 cup of cheese, sour cream, broccoli and cooked quinoa.
Season to taste with salt and pepper.
Transfer mixture to baking dish and top with the remaining 1/2 cup of cheese. Cook until cheese has melted, 5-10 minutes.
Top the casserole with the toasted breadcrumbs and serve immediately.