Poppyseed filling / Poppyseed cake and pastry filling is a staple in Russian and Ukrainian kitchens: it’s not difficult or time consuming to master and you can pre-make it even a week in advance.Ingredients:Poppy seeds .................. .. 230 gSugar ................... 230 gUnsalted butter ............ 50 gMilk ............ .. 350 mlVanilla extract ............. 2 tsp.