This is a lovely, spicy, warm flavored sauce that can be adapted by adding other ingredients. I often stir in hard-boiled eggs or bread crumbs soaked in vinegar, which adds different textures.
Serve with fish, cooked meats, cheese and salads.
Put the mustard leaves and garlic into a food processor and blend with 2 tsp vinegar. With the processor still running, add the olive oil in a slow stream, season to taste, then add the remaining vinegar if required.
Reprinted with permission from Jekka's Herb Cookbook by Jekka McVicar, Firefly Books 2012.
With almost 800 pages of recipes and striking photography, Magnus Nilsson's The Nordic Cookbook is the definitive work on the food cultures of his native land. He spoke with Melissa Clark about the impact winter has on the Nordic countries, the common source of everyone's family herring recipe, and the enduring popularity of taco quiche.