Cook the bacon. I like to line a pan with foil. Then place a sheet of parchment paper over that. I lay my bacon flat on the pan and put it into a 375 degree oven for 20 minutes. It turns out perfect every time.
Cook macaroni according to package directions, but take care not to overboil. Al dente pasta holds up better in this dish. When done cooking, drain macaroni and transfer to a large mixing bowl.
While bacon and macaroni are cooking, chop your onions, tomatoes, and green onions.
After bacon is cooked, remove it from pan and drain it on a plate covered with a paper towel. Save the bacon grease on the baking pan.
Carefully pick up your parchment paper and transfer the bacon grease to a small bowl.
Cut up or crumble the bacon when cool.
Mix the macaroni, tomato, bacon, onions, and bacon grease together.
Start with about ½ cup of mayonnaise and stir gently into the other ingredients. Add salt and pepper to taste, if desired.
Transfer to your serving bowl. You can garnish with chopped green onions, a few chopped tomatoes, and crumbled bacon if you want it to look a little fancier.
Cover and keep refrigerated until ready to serve.