I read your request and it brought back wonderful memories
of my grandmother's kitchen. She was from Bohemia and made
these weekly. I then dug out a letter from my aunt dated
1965 with this recipe. Hope it answer your needs.

Kolache (Ice Box Biscuits)
1 Fleischman's Yeast (cake)
1/2 C. Luke warm water
1/2 C. Sugar
2/3 C. Butter (See Note)
1 Tsp. Salt
1 C. Mashed Potatoes (see note)
1 Cup Scalded Milk
2 Eggs
6 Cups Flour

Put yeast in water and set aside. Cream sugar in shortening and salt.
Add potatoes & scaled milk. (both cooled) Add eggs. Add yeast and flour. Mix well. Kneed and let rise twice.
Roll out dough, cut in squares, put in fruit/poppy seed, pinch top,
place in greased muffin pans. Let rise until double in size. -
Makes 36 rolls - Bake 15 - 20 minutes at 350 until golden brown.

Prune filling - Cook in water until very soft; drain
(and pit, if necessary). Add 3/4 Cup Sugar to 1 Lb. prunes.

Note: Can use instant mashed potatoes using either just water
or half water and half milk. Have the potatoes on the thin side
as they mix in the dough much better.
Use all butter for shortening as they stay fresh longer.
Put them in the refrigerator for storage; can be heated again
if you have any leftovers.