Dry the rye bread in a preheated oven set to 200°F for 45 minutes. Once the bread has cooled, crush it in a blender or mixer until you have bread crumbs. Add the thyme, rosemary, and garlic powder, and season with salt to taste.
Dredge the 2 steaks in flour, egg, and the seasoned rye bread crumbs.
Heat some oil in a pan over medium heat and fry the breaded steaks for about 5 minutes on both sides.
Grill the zucchini, tomato, red onion, and potato slices on both sides.
Place 1 of the fried steaks on a plate, top with cheese, lettuce, the grilled veggies, and BBQ sauce, and place the other fried steak on top. Use 2 skewers to secure the sandwich if needed.