Bake bacon at 350 degrees F. on a baking sheet lined with foil until it’s very crispy, about 18-20 minutes. Pour off bacon grease, but reserve 1 tablespoon. Cook pasta according to package. Drain pasta and rinse with cold water.
When bacon is done cooking, prep your scallions by cutting the root ends off and washing them well. Dry scallions and toss them with reserved bacon grease and a big pinch of kosher salt. Spread out scallions a baking sheet. Heat oven to broil.
Broil scallions for about 2 minutes until they are charred in spots. Rotate pan if needed. Keep a close eye on them so they don’t completely burn. You might need slightly longer or shorter depending on your broiler.
Let scallions cool. Meanwhile, whisk together mayo, vinegar, mustard, and hot sauce. Stir in cooked macaroni to coat with dressing.
Roughly chop up bacon and scallions and stir into macaroni salad. Season with salt and pepper. Chill salad until served.
Notes
The salad is actually better if it can sit for a day in the fridge.Leftovers keep fine for 3-4 days and then the scallions start to get too wilted.