Preparation / Directions:
1. Lay the herring fillets in a shallow baking dish. Add the buttermilk, cover and marinate in the refrigerator overnight.
2. On the next day, drain and rinse the herring fillets well, then cut into bite-size pieces. Place the herring in a shallow glass or porcelain baking dish.
3. Combine the sour cream, yogurt, onion, apples, pickles, horseradish, lemon juice and sugar. Taste for lemon juice and sugar and add a bit more of each, if needed.
4. There should be a light lemon flavor and just enough sugar to mellow the tartness. Season the sauce to taste with salt and pepper.
5. Spoon over the herring, cover and marinate several hours in the refrigerator before serving.