Heat one tablespoon olive oil in a small frying pan over medium heat. Add diced beef fry and toss until crispy, about four to six minutes. Remove to a plate.

In the same frying pan, sauté the diced onion over a medium/high flame until golden, about 8-10 minutes, stirring constantly.

Remove onions from heat and combine with the beef fry. Set aside.

In a large bowl, combine ground beef, panko crumbs, barbecue sauce, grated onion, egg yolks, salt, and pepper.

To form uniform patties, take a three-inch jar lid. Place a small piece of plastic wrap on top. Press a small handful of ground beef mixture into the lid. Press down and level the mixture, then turn over onto a lined baking sheet. (You may refrigerate these patties until you’re ready to add the beef fry.)

Place one tablespoon of the beef fry and onion mixture in the center of half of the patties. Top each filled patty with a second, unfilled patty. Seal the edges.

Grill patties for three to four minutes on each side.