Preheat oven to 180C-360F.
In a bowl, add egg and sugar, whisk until well-combined and lighter in color.
Add oil, vanilla, and milk, whisk well.
Sift flour, baking powder, and salt. Add to previous mixture and stir gently.
Don't mind the lumps in the batter, and do not over mix, if you do the muffins will turn chewy and tough.
Spoon in muffin liners, and bake for 12 - 14 minutes or until a tooth pick inserted in the middle of the muffin, comes out clean.
Let it cool and enjoy.