Cook macaroni according to package directions; drain. Set aside.
In a medium saucepan, melt the butter over medium heat. Whisk in the flour and let it cook for a minute, then slowly add the milk while whisking. Once smooth, let it begin to simmer.
Add in 1-1/2 cups of the shredded cheese, a little at a time, whisking between each addition until all the cheese has melted into the sauce. Add in the cream cheese, salt and pepper and cook until the cream cheese has been incorporated into the sauce.
In a large bowl, stir the pasta, cheese sauce and the egg until evenly mixed.
Divide the macaroni and cheese evenly among the mini muffin tins. Press down with the spoon to pack the macaroni in, then sprinkle the remaining cheese on top of each macaroni and cheese bite.
Bake in a preheated 350º oven for 15 minutes, or until golden brown on top. Allow to cool for five minutes before removing from mini muffin pans.