1. Take the venison tenderloin out of the fridge 30 minutes before you plan to cook it. Season it well with sea salt and black pepper.
2. Peel the celeriac or neep and cut into 1cm thick slices. Cut the slices into roughly 4cm squares. Place a pan large enough to hold them all in one layer on medium heat and add 50g of the butter. Once the butter has melted add the sliced celeriac or neep and season with salt and pepper. After 2 minutes, flip them over. Once both sides are golden in colour turn the heat down to as low as it will go. Leave the veg in the pan on a low heat while you prepare the rest of the dish, turning them over after about 10 minutes.
3. To cook the venison, place another pan on medium heat, add a couple of drops of oil and the rest of the butter, the garlic and herbs. Once the butter is melted add the venison. Brown the meat on both sides, this should take about 2 minutes on each side. It is important to keep the temperature down and not caramalise the meat, as this will dry it out and make it chewy.
4. Reduce the heat beneath the pan to as low as it will go and cook for three minutes on each side if you like it rare and 4 minutes on each side for medium rare.
5. Remove the venison from the pan and wrap in foil and leave to rest while you finish the rest of the dish.
6. To pickle the brambles, place the sugar, white wine vinegar and 40ml of water in a pan and heat until all the sugar has dissolved. Remove from the heat and add the brambles.
7. Slice the venison and arrange on the plate with the slices of celeriac or neep. Drain the brambles and use them to garnish the dish. Do not discard the pickling liquor as it can be used again and also to make salad dressings. You can garnish the dish with fresh green herbs, “B. on the Road” used foraged sorrel.