Preheat the oven to 350 degrees. Grease your muffin tins with nonstick cooking spray. Bring a large pot of water to a boil. Add the macaroni to the boiling water and cook for 8 minutes until al dente. Drain and return to the pan.
While the pasta cooks, prepare the sauce. Melt butter in a large saucepan over medium heat. Add flour. Cook, whisking constantly, until lightly brown, about 1 minute.
Slowly add the cup of milk in a slow and steady stream. Bring to a boil. Cook the mixture until thick, about two minutes. Reduce heat to low.
Add cheese, one handful at a time, stirring gently. Allow cheese to melt between each addition. Remove from heat.
Add drained macaroni noodles. Stir to combine. Add egg and stir until combined. Spoon mac and cheese into prepared muffin cups. In a small bowl combine the bread crumbs and butter. Sprinkle crumb topping on the top of muffin cups.
Bake for 30 minutes in the preheated oven or until it is golden brown. Remove from oven and let cool for 5 minutes.