Spray a 9-inch cast iron skillet with cooking spray.
Boil the pasta in a large pot of salted water, following the instructions on the package, then drain it.
In a large nonstick skillet, cook ¼ of the bacon and breadcrumbs over medium heat, stirring often, until the breadcrumbs are toasted, which will take about 3 minutes.
Move the breadcrumb mixture to a cup, mix in ½ tsp of Parmesan cheese, and set it aside.
Place the red pepper, onion, and the rest of the bacon in the same skillet. Cook over medium heat, stirring from time to time, until the vegetables are soft. This should take about 7 minutes. Then, set them aside.
In the same skillet, whisk together milk and flour over medium-high heat until it comes to a boil. Then, lower the heat to medium and keep stirring occasionally. Let it simmer until the mixture gets a bit thicker, about 2 minutes.
Take the skillet off the heat and whisk in the cheddar cheese, salt, cayenne pepper, and the rest of the Parmesan cheese.
Add the cooked, drained pasta and the vegetable mixture to the skillet and toss everything together.
Transfer this mixture to the prepared skillet and evenly sprinkle the top with the breadcrumb mixture.
Bake in the oven until you see it bubbling at the edges, which should be around 15 minutes. Then, sprinkle sliced scallions on top.
Notes
Serving Size: 1¼ Cup6 Points (2022/2024 Plan)MyWW Points: 6 Blue Plan and 7 Green Plan6 WW Freestyle Points and 7 Smart PointsWe are not associated with Weight Watchers/WW in any way. Double check points on their official calculator.Refrigeration and reheating: Leftovers can be stored in an airtight container in the refrigerator for a few days. To reheat, add a splash of milk to prevent the mac and cheese from drying out, and gently reheat it in the microwave or on the stove over low heat, stirring occasionally.Freezing: This dish can be frozen, though the texture of the sauce may change slightly upon thawing. Freeze in airtight containers and thaw in the refrigerator overnight before reheating.