Cut the vegetables into small cubes and cook them in the milk and cream until they are tender in a thick-bottomed pot. This typically takes 15-20 minutes, depending on the size of the cubes.

Use a slotted spoon to lift the vegetables and place them in your blender/bowl for an immersion blender. Blend them with 1 dl of the liquid from the pot. Gradually add more of the liquid until smooth and creamy.

Put it in a new, thick-bottomed pot and heat it through on medium heat.

Season with salt, white pepper, lemon juice, and vinegar.

The purée is ready to serve.