How To make Majonezes Burgonya (Potatoes with Mayonnaise)

2 lb Potatoes
1 Onion, large
2 ts Sugar
1 ts Salt
1 tb White vinegar
2 c Water
1 lb Sour cream
3 tb Mayonnaise
1 ts Mustard
1 tb Lemon juice, fresh!
1 tb Sugar
1/2 ts Salt
Cook potatoes in their skin. Do not over cook! Peel them after cooking, slice them. Make marinade with salt, sugar, vinegar, onion and as much water as needed to cover the sliced potatoes. Let it stand over night in the marinade. (If you want to eat the onions in your salad chop them, if you don't like to eat them, slice them, so you can discard them before you make the dressing.) Strain the marinade from the potatoes make the dressing with these ingredients: sour cream, mayonnaise, sugar, lemon juice, salt, mustard. Pour over the marinated strained potatoes. Let it stand for a few hours before serving.