Interesting what you can find. Ok, these could be considered large, savory cabbage stuffed pierogies (which have a contentious origin), or a Russian concoction called Pirozhki. Same word, I think. That would sort of make sense to me since my Grandparents immigrated from a German settlement in Russia. There was probably a fair amount of Russian influence in my Mom's cooking.
I also found this recipe called a Cabbage Buger and the peppers sound like a good addition:
FOR THE ROLL:
2 pkg. yeast
1 1/2 c. scalded milk
1/2 c. butter, melted
1/2 c. sugar
1/2 tsp. salt
3 eggs, beaten
5 c. flour
FOR THE CABBAGE FILLING:
1 lb. hamburger (or 3/4 hamburger, 1/4 sausage)
1 onion, chopped
1 head cabbage, chopped
1-2 green peppers (optional)
Mushrooms (optional)
FOR ROLLS: Put yeast in bowl; set aside. In saucepan, scald milk, then add butter, sugar, and salt. Cool until lukewarm, add 1/2 cup of the milk mixture to the yeast, stir to dissolve. Add remaining milk, stir. Next, add the eggs, stir. Add 1 1/2 cup flour, beat until smooth. Gradually add in remaining flour.
Form dough into a ball and place in greased bowl and cover with damp cloth, let raise until doubled. Punch down the dough and roll out on floured surface. Cut into squares and place cabbage filling in the center of square, bring together the corners and pinch edges together.
FOR THE FILLING: In large skillet, brown together the hamburger, onion, green peppers, and mushrooms; add salt and pepper to taste. When nearly browned, add chopped cabbage. Heat for 1-2 minutes. Drain. Place filling in center of rolled-out dough square and pinch together edges. Bake 25 minutes in 350 degree oven. Brush rolls with butter when done baking.