- 2 sweet onions, peeled, and halved
- 2 cups mayonnaise
- salt and pepper to taste
- Preheat oven to 400 degrees F (200 degrees C). Line a baking sheet with aluminum foil and lightly grease.
- Place the halved onions onto the baking sheet, and roast in the preheated oven until they have turned deep golden brown, and have softened in the center, about 30 minutes. Remove from the oven and allow to cool to room temperature.
- Place the onions into a food processor or blender, add the mayonnaise, and puree until smooth. Season to taste with salt and pepper. Store in the refrigerator.