Heat olive oil in a large skillet. Add onions and salt. Saute 35 to 40 minutes until golden brown, stirring occasionally. Set aside to cool.
Place cooled onions in food processor. Pulse several times to chop. Remove 1/2 of the onions and place in a mixing bowl. Add the remaining ingredients to food processor. Process until smooth. Spoon into mixing bowl and combine with chopped onions.