Cut the puff pastry into 4 long strips and spread a thin layer of crème fraîche. Cover with 2 slices of raw ham and 3 asparagus and roll everything up. Brush the asparagus rolls with egg yolk and place on a baking sheet.
Place the asparagus rolls in the oven, which has already been preheated to 200 degrees, and bake until golden brown for approx. 20 - 30 minutes (note the empirical values of your own oven).