Cook under a medium light for about 5 minutes, then gently turn each apple and shallot slice with a fork or with the metal spatula and cook them for 5 more minutes. If you finish cooking the shallots but have more apple slices that could not fit into the pan in the first single layer, push the shallots off to the side, on top of apple slices and cook the rest, or remove the shallots to a warmed plate while you finish cooking the remaining apple slices.