Grill hot dogs off first over high heat and get a good char on all sides. Set aside and allow to cool to the touch.
When hot dogs are cooling, assemble the mac and cheese. Preheat the oven to 350 degrees.
In a large stock pot, cook macaroni to directions on back of box. While pasta cooks, assemble the cheese sauce. In a large sauce pan, add the 3 Tbls butter and the flour. Whisk to combine and form a paste, add in the salt and pepper, ½ tsp paprika, ½ tsp garlic powder and ½ tsp onion powder. Add in the milk and mustard and whisk to combine. Bring to a simmer over medium heat and let cook for 10 minutes until thickened. Temper in the egg and take off the heat. Add in 2 Cups of the cheese.
Add cooked pasta into the cheese sauce pot and with a spoon mix until pasta is coated. Cut up hot dogs into rounds and mix with macaroni filling. In a baking dish sprayed with cooking spray, add in the pasta mixture. Add the chili in a layer on top. Top with remaining cheese.
Mix the onions and breadcrumbs with the melted butter. Cover entire dish with this mixture.
Place in oven for 30 minutes, uncovered until bubbly. Take out of oven and let sit for 10 minutes before serving, enjoy!