Devilled kidneys with Nordic mustard & Gentleman’s Relish

Method

1. For the mustard, put all the ingredients into a blender and leave to soak for 30 minutes. Whizz until smooth, then transfer to a sterilised jar.
2. Heat a griddle pan. When hot, griddle the sourdough slices for 1-2 minutes on each side until char marks appear, then set aside.
3. Cut the kidneys in half lengthways. Season well and rub lightly with oil. Cook on the hot griddle pan until well seared on all sides (or for 6-8 minutes longer if you prefer them more well done) then transfer to a plate. Rest for 5 minutes.
4. Meanwhile, make the sauce. Put the cream into a medium saucepan over a medium heat. When warm, add the rest of the sauce ingredients and whisk until well combined and the butter has melted.
5. Once rested, cut the kidneys into bite-size pieces and add to the sauce along with any resting juices. Put the pan back over a low heat to warm the kidneys through. Season to taste, then serve on top of the chargrilled sourdough. Sprinkle with parsley and black pepper.