If you don't have Maldon smoked sea salt, just season with the biggest, flakiest salt you have. Another Note: Odds are very good there is going to be liquid marrow fat left over in the pan. Do not waste this! If you have some crusty white bread, plop a few slices in the pan and slide back in the oven for a few minutes to produce the best toast you've ever had. Or simply pour the fat into heat-proof containment, cool, cover tightly, and refrigerate for later use.