Heat oil in a medium skillet over medium heat. Add onion and garlic. Let sweat for 2-3 minutes, stirring occasionally. Increase heat to medium-high and add ground beef. Stir to break up the ground beef and combine. Let cook 4-5 minutes. Add barbecue sauce, Worcestershire, chili powder, salt, and pepper. Reduce heat to low. Let simmer 5-10 minutes. In a large skillet or griddle over medium heat, melt 1 tbl. of butter. Add 4 slices of Pane Turano and top with 1 ½ oz. of each cheese. Let begin to melt, about 2 minutes. Top one side each with sloppy joe mix and close up each sandwich. Repeat steps 5-7 with remaining sandwiches and serve.