Cook the bacon. Line a plate with a paper towel. Heat a skillet to medium heat and saute the bacon until golden brown and crispy. Remove the bacon from the pan with a slotted spoon and allow it to drain on the lined plate.
Make the pasta. Cook the macaroni according to the instructions on the package (don’t forget to salt the pasta water). Drain the pasta and set aside.
Make the bechamel. Heat a large saucepan over medium heat. Melt the butter. As the butter starts to bubble, whisk in the flour. Cook for 1-2 minutes, mixing continuously. Add the milk, 1 cup at a time, stirring continuously. Turn the heat to medium-low and allow the bechamel to simmer for a few minutes until thickened. Season with salt and pepper.
Make it cheesy. Stir in the cheese, 1 cup at a time, allowing each addition to melt into the sauce before adding the next. Turn off the heat.
Put it all together. Stir the macaroni into the sauce along with the cooked bacon and serve.