Crumble the yeast in a bowl and pour in the water and stir until the yeast is dissolved
Mix the sugar in the bowl
Mix half of the flour and salt in the bowl and stir
Add the rest of the flour and stir with a wooden spoon or dough scraper until the dough is uniform
Put the dough in the fridge and let it rise for 30 min
Roll out the cold butter to 20 x 20 cm between two pieces of baking paper with a rolling pin
Sprinkle the kitchen table with flour and roll out the dough to 40 x 40 cm. Put the butter in the middle of the rolled out dough and fold all sides up around the butter and lightly press the dough together, so the butter is completely covered with dough. Put the dough on a cutting board and leave it in the fridge until it is completely cold (about 30 min)
Sprinkle the kitchen table with flour and roll the dough oblong to 40 x 80 cm. Fold both ends in towards the middle. Then fold the dough together once. There should be 4 layers of butter after the dough has been folded. Put the dough back on to the cutting board and place it in the fridge until it is completely cold (about 30 min)
Repeat step 8 once more
Sprinkle the kitchen table with flour and roll out the dough to 30 x 60 cm. Stick out 20 hearts with a heart shaped cake slicer (about 10 cm in diameter). Then make holes shaped like hearts in the middle of half of the large hearts with a small heart shaped cake stick (about 6 cm in diameter). Save the large hears, the hearts with a hole, and the small hearts. Use excess dough by placing leftovers on top of each other and rolling it out into a new piece the same thickness as the old one and sticking out more hearts
Place the large hearts (without a hole in) on baking paper and brush their top with a little water. Place a heart with a hole in the center on top of each of the hearts on the baking paper. Also place the small hearts (from the holes) on baking paper.
Let the buns rise for 2 hours with a kitchen cloth on top or let them rise in the fridge overnight
Bake the buns in the oven for 10-15 minutes at 190°C
Allow the buns to cool before adding the cream. Make the cream in the meantime