Sweet yeast dough for Czech kolache:

• Heat half of the milk until it is lukewarm – test the temperature with the tip of your little finger.
• Add a tablespoon of sugar.
  
• Mix in the active dry yeast and let it leaven for 15 minutes in a warm place.
  
• Meanwhile, warm the rest of the milk up until it turns lukewarm, and melt the butter. The butter must be liquid, but not hot!
• Put the flour into a bowl, add sugar, salt, egg yolks, melted butter, lemon zest, vanilla, milk, and leavened yeast.
  
• Knead the dough until smooth and springy. It takes about 5 minutes.
  
• Cover the bowl with a clean towel and keep it somewhere warm for an hour to let it leaven. You can dust some flour on the dough so that it doesn’t get dry. However, don't cover it with grease – you'd slow down the leavening.
  
• While the dough leavens, prepare the fillings for the kolache.
• Divide the leavened dough into small pieces, each about 2 inches in diameter. Roll between your hands round scones and lay them down on a tray, which you have previously greased with butter (you can also put a layer of parchment paper on your baking sheet).
• Scones will leaven, so leave enough space between them, on one tray (13 x 9 inches) will take about 9 kolache.
  
• Let the scones leaven for about 30 minutes, DO NOT skip this step!
• Preheat the oven to 350° F (180 °C).
• Take a flat-bottom glass, cover it with a clean towel (you can also dust the glass bottom with flour), and press the scone's middle with the glass carefully. You'll create a flat kolach with the place for the filling.
  
• Glaze the edge of the kolache with the beaten egg.
• Put the filling of your choice in the middle of the kolache, then sprinkle it with streusel (DROBENKA).
  
• Bake kolache in the oven for about 20-30 minutes, until the edges turn golden brown.
• Let the kolache cool down and separate them from the tray carefully. They taste the best when eaten on the same day they were baked!