Preheat oven to 350 degrees. Grease an 8x8 inch casserole dish with cooking spray.
Rinse quinoa. Place in a pot with water and 1/4 teaspoon of salt. Bring to a boil; cover, reduce heat medium-low and simmer for 18-20 minutes, or until water is gone. Fluff with a fork and allow to cool slightly. (Alternatively, use 1 1/2 cups leftover cooked quinoa.)
In a large bowl, combine soup, yogurt, milk, cheese, sugar, paprika, pepper and nutmeg. Add cooked quinoa, broccoli and tuna. Check for seasoning - I found mine needed a pinch of salt and a wee bit more pepper! Spoon into prepared casserole dish and sprinkle with a few tablespoons of Parmesan cheese. Bake for 35-40 minutes, or until the top is bubbly and golden.