At 1 cube of yeast is added about 50 ml warm milk, a pinch of salt, a pinch of sugar. Mix to dissolve and add flour 1-2 tbsp. First a spoonful of flour, stir and if necessary add a little more. You should get a thick smooth paste as boza. Allow to warm to swell until doubled in volume, but not more, because if overdone will fall and there will be no effect.