There are some ingredients that are unbeatable with smoked fish, and you’ll find them all here. Horseradish gives the butter an icy heat, and the chives add a spiky freshness, but they’re both tempered by the cool green watercress. The overall effect is like a fine soft cheese which literally melts in your mouth. All you need is a pack of your favourite butter, a small bunch of trimmed, finely chopped watercress, 2 tbsp of chopped chives and 2 tbsp of creamed horseradish. Whip the whole lot together, using a mixer of you have one, until it's light, fluffy and lime green. Taste, add a little salt and pepper if needed, and serve on smoked fish, baked potatoes or practically anything else you can find.