In a medium sized bowl, mix the sour cream, horseradish, mayonnaise, lemon juice and zest, and caper brine until well combined. Season with salt and white pepper (black pepper is fine if you don’t have white).

Cover the sour cream mixture tightly and place it in the fridge for at least 30 minutes or up to a few hours to allow for the flavors to marry. Remove from the refrigerator 15 minutes before serving.

To make the cakes: Place the cubed potatoes into a large pot of salted water and bring to a boil. Boil until they can be pierced with a knife, but not crumbling or breaking apart. Drain and spread out on a sheet pan to cool. Once cooled, break up a little with a fork so you have a variety of sized pieces. Do not mash or make too small. You want different textures of potato in the cakes.

Prepare a wire cooling rack set over a paper-towel lined sheet pan, and a second sheet pan to place formed cakes. Set aside.

In a large bowl, mix together the cooled potato chunks, smoked fish, scallions, dill, capers, mayonnaise, lemon juice & zest and eggs. Season with salt and pepper. Mix gently so as to not break up the potato too much. After it’s mixed, sprinkle the flour on top and give it one more mix to incorporate all of the flour.

Using a ⅓ cup measure, scoop out the mixture and with lightly oiled hands, form into uniform balls, resembling large meatballs. Place the formed balls on a sheet pan and transfer to the refrigerator for 30 minutes to firm up. You can make these a few hours in advance and keep chilled until ready to fry.

Once the cakes have chilled, heat schmaltz and vegetable oil (50-50 mix) in a large frying pan (cast iron or nonstick work best) to medium high heat. Oil should fill pan to 3/4” in depth. Dust the potato balls lightly with flour on all sides, and add them to the pan with at least 1-2” between them. After a minute, flatten the balls down into a cake with your hand or a flat spatula so they are about 1 ½” high. (It’s ok if the edges separate a little and become uneven when you flatten them. They will fry up with crispier edges and surfaces!). Reduce heat to medium and continue cooking for 3-4 more minutes until golden brown and crispy. Flip gently and continue cooking on reverse side for another 4-5 minutes. The cakes should have an all-over golden brown, crispy exterior. After cooking, transfer to wire cooling rack over the lined sheet pan to cool for a few minutes.

Serve immediately with horseradish sour cream and some freshly chopped dill and/or parsley. If you’re feeling festive, a dollop of caviar always makes everything better!