If you haven't already done so, gut the herring and give it a rinse out. Cut the head & tail off the herring leaving the bones in and skin on. You should be able to open out the fish so you have one butterflied fillet rather than taking a fillet off each side of the fish. You can remove the skin & bones if you like so you have 2 small fillets from each fish, this is just the way we prepare them here in Scotland

Put the mixed oatmeal in a shallow dish large enough to hold a butterflied fillet

Open out the fillets and press them into the oatmeal. You don't need to use egg or anything, the natural moisture will hold the crust on. Coat both sides, really press it on to get a good coating

Heat some oil in a frying pan and put the fish in skin side down over a medium heat

Fry for 2 minutes then turn each fillet over and fry another 2 minutes on the other side or until done