Heat the oil in a large nonstick frying pan over medium heat.

Add the onions and cook, stirring occasionally.

When they begin to brown, sprinkle 1 tsp sugar over the onions and continue to cook until they reach a caramel color.

When done, drain on paper towels, transfer to a bowl and chill about 1 hour.

After that time, place the onions, sour cream, buttermilk and salt in your food processor. Blend until combined.

Chill another hour for the flavors to develop and serve with chips.