I used red onion, but any type of onion works just fine. I used red potatoes without skin, but you can leave the skin on if you like it. I used chives from the garden but if you do not have, you can also use a bit of spring onion. I used white beans since I find they have a richer taste but I think would work well with other type of beans as well. If you do not have sour cream you can prepare my home made version (1 cup cashews previously soaked in hot water for 30 min to 1 hour, depending on the time you have. Then drained and blended with 2-3 tbsp vegan yogurt, 50 ml water, 1-2 tbsp lemon juice, 1/2 tsp salt. Blend everything until you get a smooth paste similar to thick yogurt. Adjust the sourness by adding more or less lemon juice. Start with one tbsp and add more as you blend if you prefer it so. That will be your sour cream). Enjoy!