Drain herring fillets and reserve the onion. Slice each apple half into 12 thin slices. Cut each slice of bread in half. Spread rounded teaspoon of goat cheese onto bread. Top goat cheese with one slice of apple, then one piece of herring and one or two pieces of reserved onion. Garnish with grated radish and sprinkle with sea salt.
This sweet and salty mixture will excite the taste buds and leave you wanting more