I finally remembered to ask my mom for her potica recipe when we went home for Christmas. Since my nephew and my sister are allergic to nuts, she no longer makes the walnut version, only the poppyseed, which I do not prefer. Now I can make my own

I didn't find it difficult or time consuming to make at all. There is no attribution on the typed, schmeared card she scanned for me. I made a half recipe, which made two large loaves. A full recipe makes 3 very large (long and skinny-ish) loaves. I think she bakes them in long skinny pans, but I just set them side by side on parchment on a baking sheet and they were fine.
Linda's Potica
Dough
3 T sugar
1 1/2 t salt
4 c flour
1 stick butter
3 egg yolks
1 c sour cream
1 cake yeast ( I used 2 1/4 t instant)
1/4 c warm water
1 t sugar
Sift or whisk the sugar, salt and flour. Cut in butter as for pie crust. Dissolve yeast in water, add sugar. Let stand until it foams. Mix egg yolks and sour cream, add foaming yeast. Make a dent in flour and add liquids. Mix well and knead gently. Place in a bowl and refrigerate overnight.
Filling
1 1/4 lb nuts (usually walnuts)
4 egg whites
1/4 lb butter
1 c boiled milk
1 egg yolk
1 c sugar
Grind nuts finely. Add butter and sugar to boiled milk. Pour over nuts and let set till egg whites beat stiff. Fold egg whites into nut mixture.
Finishing
Divide dough into 3. Roll out each piece and spread with 1/3 filling. Roll up and place in pans seam side down. Slightly beat egg yolk and brush on top of dough. Let rise in warm place 1 to 1 1/2 hours. Bake at 325 for 45-60 minutes.