Prepare yeast dough and let it rise once (see Easter yeast plait).
Line two baking trays with baking paper. Knead the dough well again on a floured work surface. Divide into about 12 portions and form round rolls. Distribute on the baking trays. Let it rise again for about 10 minutes.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Whisk egg yolk with 2 tbsp. water and spread on the rolls. Bake in the hot oven for 12-15 minutes one after the other.
Remove and let it cool down.
Chop the couverture, melt with coconut oil in a warm water bath. Cut the rolls in half horizontally. Dip the tops of the buns into the chocolate coating. Let dry on a cake rack.
For the foamy kiss filling, beat the egg whites and 1 pinch of salt in a warm water bath with the whisks of the mixer until stiff, letting the sugar trickle in. Beat until the sugar has dissolved and the mixture is shiny.
Pour into a piping bag with a large star-shaped spout. Pour onto the lower halves of the buns. Spread raspberry spread on top. Put the lid on and dust with icing sugar.