Working with one slice at a time, dredge the meatloaf first in the flour and then in the egg, coating it on all sides and shaking gently after each dip to knock off the excess. Lay the meatloaf in the crumbs, scatter some crumbs on top of the slice, and press gently to adhere. Flip and repeat once or twice with the crumbs to coat really well; be sure to get the edges as well. As you finish each slice, set it on a tray. When all are coated, refrigerate for at least 5 minutes and up to 1/2 hour to let the breading set up. Save some of the leftover crumbs for testing the frying oil
temperature and discard the remaining breading ingredients.