I used to get kolaches in Chicago as a child at the Calumet Bakery, which I understand is still open. The owner was named Matt Pocernich, and I don't know what his nationality. The kolaches were really light and flakey, almost like puff pastry, folded in like a pinwheel, with fruit or poppyseed or cheese fillings, and powdered sugar on top.
Though I do like the Texas Czech kolaches, they are completely different, yeast dough-based, heavier.
I have never been able to find a recipe for the memorable pastries from the Calumet Bakery.