Cook the pasta according to the package instructions, until al dente. Strain and run under cold water and stir so that the pasta immediately stops cooking.
Melt the 2 tbs butter in a medium skillet, over medium heat. Whisk in the flour until smooth, and let it cook for a minute to get rid of any flour taste.
Whisk in the broth a little at a time, and stirring constantly until the evenly combined and smooth. Continue cooking, stirring frequently, until the roux has thickened. Reduce the heat to low, add the cubed cheese,and cook, stirring occasionally, until cheese is melted; about 4-5 minutes.
Transfer the cheese sauce to a large bowl. Stir in the condensed soup until evenly incorporated.
Add the pasta and meatballs, stirring to evenly incorporate/distribute.
Lightly spray a large baking dish with non-stick cooking spray. Transfer the pasta and meatballs into the baking dish, using a spatula to scrape the bowl for any missed sauce.
Mix the 1 tbs melted butter with the crushed cracker crumbs. Stir well to evenly coat, and sprinkle the buttered crumbs evenly out over the top of casserole.
Bake at 350 degrees for 35-30 minutes, until the casserole is bubbly and the cracker crumbs are golden brown.
Let it rest for one minute. Top with fresh, chopped parsley, if desired and enjoy.