Heat olive oil in a saucepan over medium heat. Add onions and stir to coat evenly in the olive oil. Reduce heat to low and allow onions to cook, stirring occasionally. If they begin to stick to the bottom of the pan add a tablespoon of water and stir to release onions. Continue to cook the onions until they reach a dark golden brown color. Remove from heat and set aside.
Mix the sour cream and mayonnaise in a medium sized bowl. Add in the herbs and spices and stir until combined.
Top the dip with the caramelized onions and serve with carrots.