Italian Juicy Lucy

Directions

1. Preheat a grill to medium-high; at least 5 minutes for a gas grill. For a charcoal grill, heat the charcoal to very hot with an ash coating, then push the coals to one side of the grill. When the grill is ready –you should be able to hold your hand one inch above the grill grates for only a second– lightly rub the clean grill grate with an oil soaked paper towel using a pair of tongs.
2. Cut the focaccia into 3½-inch squares, split. If desired, trim each slice to ¾-inch thick. Set aside.
3. Stack the four slices of fontina cheese. Cut in half, then cut each piece in half again to form four bricks of cheese. Set aside.
4. In a large bowl, add the ground beef, salt, garlic powder, Worcestershire sauce, pepper and crushed red pepper flakes in a large bowl. Gently mix with your hands until just evenly combined.
5. Divide the beef into 8 equal portions (3 oz each) and form each into a ball.
6. Form one juicy lucy at a time pressing 2 portions into round 5-inch diameter, ¼-inch thick patties on pieces of parchment paper.
7. Top one patty with 2 teaspoons basil pesto and 1 cheese brick.
8. Place the second patty on top and pinch the edges to form a tight seal. Cup the stuffed patty with your hands to round out the edges, and press on the top to flatten slightly into a single thick patty. Transfer to a plate. Repeat with the remaining patties and cheese to form 4 stuffed burgers in total. Getting a good seal on the edges is important so you don’t lose the cheese during grilling.
9. Chill for 30 minutes.
10. Meanwhile, sauté a thinly sliced onion over medium heat in 1 tablespoon olive oil and a pinch of salt until soft and golden brown. (Can be done several hours ahead.)
11. Brush both cut sides of the focaccia lightly with olive oil and grill, cut side down, until the buns are lightly toasted. Set aside until needed.
12. Remove the burgers from the fridge and give each a light brush of olive oil. And a pinch each od salt and pepper.
13. Place the burgers onto the hottest part of a grill, oiled side down.
14. Sear the burgers for 3 minutes per side and then move them to the cooler edges of the grill (or lower gas to medium low).
15. Cook for another 3-4 minutes per side on the edges of the grill to 160°F. Do not press down on the burgers during cooking. Remove the burgers from the grill.
16. To assemble: on the bottom buns, place some arugula and a spoonful of the sauteed onions. Top with a stuffed burger, a spoonful of pesto and sliced red peppers. Add the top bun and skewer with a pepperoncini.
17. Serve immediately.