Ingredients
15 ml vegetable oil, or as needed
1 large onion, thinly sliced
30 g butter
30 g white sugar, or as needed
240 ml sour cream
240 ml plain yogurt
120 ml mayonnaise
salt and ground black pepper to taste
Directions
Step 1
In a skillet over low heat, warm the oil and add the sliced onion. Cook and stir until the onion is soft but not browned, about 20 to 30 minutes. Increase the heat to high, add the butter, and sprinkle the sugar over the onions. Cook and stir frequently until the onion is very tender and dark brown, about 8 to 10 minutes. Remove from heat and let it cool to room temperature.
Step 2
In a bowl, combine the sour cream, yogurt, and mayonnaise. Season with salt and black pepper. Mince the cooled onions on a cutting board and stir them into the sour cream mixture. Refrigerate the dip to allow the flavors to blend, at least 1 hour.