In a small saucepan, combine the evaporated milk, sugar, vinegar, vegetable oil, and garlic powder.
Heat the mixture over medium heat, stirring constantly, until the sugar has dissolved.
Remove the sauce from the heat and allow it to cool.
The sauce can be stored in the refrigerator for up to a week. To serve, drizzle the sauce over slices of donair meat or use it as a dip for the meat.
Note: Some variations of this recipe call for the addition of a small amount of dry mustard or paprika for added flavor. You can also try adding a bit of hot sauce or Worcestershire sauce for a spicy kick. Experiment with different ingredients to find the perfect balance of flavors for your taste. Enjoy!