1In a small bowl combine the two cheeses and set aside.
2Melt butter in a skillet over medium heat add onions and cook until very caramelized, and dark golden brown 20-30 minutes.
3With a slotted spoon transfer onions to a bowl. Add beef to skillet; cook and stir until beef is evenly brown, 2-3 minutes.
Return onions and any juice to the pan. Add flour, brown sugar, cumin, salt, pepper, and beef stock to pan. Cook and stir (scraping the bottom of pan) until most of the liquid is absorbed.
4Heat oven to 375
Grease cookie sheet or use a Silpat mat.
Separate dough into 8 triangles. Slightly overlap 2 triangles with the longer sides together to make a larger triangle. Repeat with remaining triangles to create 4 larger triangle.
Place triangles in a row on cookie sheet slightly overlapping the top point on on triangle with the bottom of the next triangle
5Evenly spoon beef and onion mixture down the centers of the triangles in a 1 1/2 inch strip, beginning and ending one inch from the end.
6Sprinkle cheese mixture over onion mixture.
7Bring points over filling. Cross one over the other to make a braided appearance. Seal ends and sprinkle with 2 Tablespoons of Parmesan cheese.
8bake at 375 for 15-20 minutes or until deep golden brown. Let rest for 5 minutes, serve with sour cream or yogurt if using, and heated au jus gravy