I absolutely love this dish, it’s where comfort meets elegance. The rumps of lamb are juicy and wrapped in a vibrant herb crust that bursts with flavour, while the mushroom duxelles adds depth and earthiness. A flash of buttery rainbow chard brings freshness, and the pickled walnuts cut through it all with the perfect sharp note.
Ingredients
for the rumps of lamb:
- 4 rumps of lamb (170g each)
- 100g rainbow chard
- 100g butter
- 50g dijon mustard
- salt
- pepper
For the pickled walnuts:
- 200g green (unripe) walnuts
- 250ml malt vinegar
- 100g sugar
- 5 cloves
- 2 cinnamon sticks
- 5 black peppercorns
- 2 bay leaves
For the mushrooms duxelle:
- 500g chestnut mushrooms finely diced
- 150ml Madeira wine
- 50g butter
- 2 garlic cloves
- thyme
- salt
- pepper
For the pomme pureé:
- 500g rooster potatoes
- 120g butter
- grated nutmeg
- 50ml full-fat milk
- salt
For the herb crust:
- 60g breadcrumbs
- 10g tarragon leaves
- 10g parsley leaves
- 10g chives
- 20g parmesan cheese
instructions
For the mushrooms duxelle:
Finely dice 500g of chestnut mushrooms, or pulse them in a food processor until they resemble a coarse paste. In a large pan over medium heat, melt 50g of unsalted butter and gently cook 2 finely chopped garlic cloves for about a minute, being careful not to let them brown.
Add the mushrooms along with the leaves from a few sprigs of thyme, and cook on medium-high heat. Stir regularly as the mushrooms release their moisture, which will take around 5 to 7 minutes.
Continue cooking until the mixture becomes dry and concentrated, then deglaze the pan with 150ml of Madeira wine. Let the wine reduce completely, stirring frequently, until no liquid remains and the mixture becomes thick and paste-like, this will take an additional 10 to 15 minutes.
Season with salt and freshly ground black pepper to taste. Remove from the heat and let the duxelles cool completely before using.
For the pomme pureé:
Preheat your oven to 200°C (fan 180°C). Wash 500g of potatoes (such as Maris Piper or Yukon Gold) and prick them with a fork. Place them directly on the oven rack and bake for about 1 hour, or until completely soft inside and crisp on the outside.
Once baked, remove the potatoes from the oven and let them rest for 5 minutes. While still warm, cut them in half and scoop out the flesh. Pass the hot potato flesh through a fine sieve, this step ensures the purée is ultra-smooth.
Over low heat, gently stir in cubed unsalted butter, a few pieces at a time, allowing it to emulsify into the warm potato. Then slowly incorporate warm full-fat milk, mixing until the purée reaches a smooth and velvety consistency. Grate in a touch of fresh nutmeg and season to taste with salt.
For the pickled walnut:
To make quick pickled walnuts, start by pricking 200g of green, unripe walnuts all over with a fork. Soak them in cold water for seven days, changing the water daily to remove bitterness. After soaking, boil the walnuts in fresh water for 10 minutes, then drain. Repeat this boiling and draining process three times over consecutive days to soften the walnuts and further reduce bitterness.
Meanwhile, prepare the pickling brine by combining malt vinegar, sugar, cloves, cinnamon sticks, black peppercorns, bay leaves, and an optional small piece of ginger in a saucepan. Bring the mixture to a boil and then simmer for 5 minutes. Place the walnuts into sterilised jars and pour the hot pickling liquid over them, ensuring they are fully submerged. Seal the jars and allow them to mature for at least four weeks before using. The resulting pickled walnuts add a tangy, spiced note perfect for accompanying lamb or cheese.
For the herb crust:
In a food processor, combine breadcrumbs, fresh tarragon leaves, parsley leaves, chopped chives and finely grated Parmesan cheese. Blend until the herbs are finely chopped and the mixture becomes evenly green and fragrant.
Use immediately by pressing it onto the surface of your lamb that has been brushed with Dijon mustard to help it adhere.
For the rumps of lamb and plate up:
Sear the rumps of lamb in a hot pan with a little oil until they develop a deep, even caramelisation on all sides. Once well-coloured, add a knob of butter and a crushed garlic clove to the pan. Baste the lamb briefly, then transfer the pan to a preheated oven at 180°C and roast for approximately 8 minutes. Allow the meat to rest for 5–7 minutes before slicing and serving.
Quickly sauté the rainbow chard leaves in butter with a pinch of salt. Cook just until wilted, about 10 seconds, to preserve their vibrant colour and delicate texture. Avoid overcooking to keep the leaves tender and fresh.
Gently spread a thin layer of mustard over the rumps of lamb, then press them firmly into the herb crust to ensure it adheres well.
On each plate, spoon a generous portion of hot pomme purée alongside a neat mound of mushroom duxelles. Add the sautéed rainbow chard and carefully lay it on top of the lamb slices. Finish the dish by garnishing with pickled walnuts for a touch of acidity and texture, and serve with a rich, flavorful lamb jus on the side.