For the cheeseburger bites, combine the ground beef, egg, and bread crumbs, and season with salt and pepper. Press about ¾ of the seasoned ground beef mixture into the molds of a large silicone ice cube tray. Push a cheddar cheese cube into the center of the meat in each mold and cover with the remaining seasoned ground beef mixture. Transfer the ice cube tray to the freezer and freeze for 2 hours.
For the gravy, heat some olive oil in a pan over medium heat and fry the mushroom slices and diced red onion. Pour the red wine into the pan and let it reduce. Stir in the vegetable stock, season with salt and pepper, and let the sauce simmer for 15 minutes.
Heat a large pot of cooking oil to 325°F and cut the potatoes into wedges. For the batter, combine the beer and flour. Remove the cheeseburger bites from the freezer, dip them in the batter, and roll them in the bread crumbs. Deep-fry the breaded cheeseburger bites and the potato wedges in the hot cooking oil for 5-8 minutes.
For the disco fries, season the hot potato wedges with salt and garnish with shredded mozzarella, gravy, crumbled feta, radish slices, and parsley. Place the fried cheeseburger bites on top and enjoy!