Cut the bacon into 1cm wide strips.

Thinly slice the onion.

Heat salad oil in a frying pan, add bacon and onion, and sauté over medium-low heat until the bacon is crispy and the onion becomes tender.

Boil water in a pot, add salt and macaroni, and cook according to the package instructions. Drain the water.

Place the hot macaroni in a bowl, add vinegar, and mix. Add the sautéed bacon and onion mixture, and let it cool slightly.

Add mayonnaise and salt, mix until well combined. Add the boiled egg, roughly mash it, and mix gently.