Potato salad with mayonnaise and lilac onion

This is our traditional family recipe. When  my family come together we eat this salad. This is perfect as side dish or on it's own. 

You'll need:

10 medium size potatoes

200 ml sour cream 

2 lilac onion

ground pepper

a little bit of sugar

salt

and for the mayonnaise:

2 yolks

1 pinch of salt

1 tbsp of mustard

250 ml of vegetable oil

1 tsp of lemon juice

The easy process:

Wash the potatoes and cook them until tender. During the cooking, peel the lilac onion and cut into thin slices. When the potatoes are cooked set aside for cooling. Now peel and cut the potatoes into slices, season it with salt. The thickness of the slices depends on You, do it just how thick You like it.

Making the mayonnaise is very easy, but You have to be patient and careful. Whisk together the yolks, the salt and the mustard. Stir continuosly and add the vegetable oil. You have to stir 'till the yolks soak up the whole amount of oil. Now add the lemon juice and more salt if it's needed. Your mayonnaise is ready. ( I have to confess, that I had several "mayonnaise failure" before my first real mayo....)

Now add the sour cream and the sugar tho the mayo and mix everything together. Put the salad in a big bowl and set into the fridge for an hour to cool it down well.

As a side dish this is perfect for roasted meats.