Melt butter in a large skillet on medium-high. Add sliced onions, reduce heat slightly and cook, stirring occasionally, about 25 minutes. Onions should gradually turn golden brown – if they start to brown too quickly, turn down the heat. Once they become golden brown, add several tablespoons of water to the pan and scrape the bottom to release the caramelization. Season onions with salt and pepper. Remove pan from heat and allow onions to cool about 10 minutes.
In a food processor, add cooled onions and remainder of ingredients. Process until smooth, scraping the sides of the bowl as necessary.
Makes approximately 2 cups.
Tip: This dip pairs nicely with Mann’s Sugar Snap Peas.