Put the sour cream, curry, lemon juice and egg yolk in a bowl and whisk with a whisk. First put aside.
Bring the broth to a boil, cut the carrot and apple and add to the broth. Cook until the carrots are tender (about 15 minutes). Then puree everything.
When everything is small, add the sauce made from sour cream and curry. Let it boil a little more, add the pineapple and cook again for 5 minutes and season to taste.