Method
1. Line a baking tray or plate with baking paper. Spoon the butter and honey into a large frying pan. Add a pinch of chilli flakes and a pinch of salt. Set over a medium heat and let them melt together. Add the walnut halves and cook, stirring often, for 2-3 mins till the sauce has reduced and the walnuts are coated. Scoop onto the tray. Set aside to cool. Keep the frying pan for later.
2. Fill a large pan with water, pop on the lid and set on a high heat to come to the boil. Slice the leaves off the woody cavolo nero cores. Discard the cores (see our tip on how to use them up) and finely slice the leaves. When the water in the pan is boiling, add the cavolo nero and simmer for 1 min to blanch. Use a slotted spoon to lift the cavolo nero out of the hot water. Set aside in a colander to drain. Take the water off the heat, but keep it for later.
3. Trim the roots and woody greens off the leek. Slice a cross in the top to open it out and rinse out any grit. Finely slice the leek. Thickly slice the mushrooms. Finely chop a handful of sage leaves.
4. Set the frying pan back on a medium heat and pour in the cider. Add the leek, mushrooms and sage. Season with salt and pepper and bring to a gentle bubble. Pop a lid on the pan (or use a baking tray if you don't have a lid) and gently simmer, stirring often, for 15 mins till the cider has almost entirely cooked off and the veg are tender and juicy.
5. Put the pan of water back on a high heat. Add a generous pinch of salt, cover with a lid and bring back to the boil. When the water is boiling, add the pasta and simmer for 10-12 mins till the pasta is tender but still has some bite.
6. While the pasta cooks, turn the honeyed walnuts out onto your chopping board and roughly chop them. Crumble the stilton and finely grate the Italian hard cheese.
7. Check the veg, and if the cider has reduced, add the cavolo nero to the pan. Keep the lid off and warm through for 1-2 mins. Add the stilton and most of the hard cheese. Stir till the cheese has melted. If it seems a bit dry, ad a few tbsp milk or double cream. Taste the sauce and add a pinch more salt and pepper, if you think it needs it.
8. Drain the pasta and add it to the stilton and cider sauce. Toss to mix. Divide between warm plates or bowls and top with the remaining grated cheese. Sprinkle with some honeyed walnuts to serve.
9. No Waste, More Taste
Leftover cavolo nero cores can be sliced and added to crisp coleslaws, chopped and chucked into soups and stews, or lightly pickled in a sugar and salt brine to make crunchy pickles that are delicious served with charcuterie boards.
10. Love Your Leftovers
You may not want to add all your honeyed walnuts to your pasta dish. Any leftover walnuts will keep in a tub for up to a week. Add the to salads, use them to top soups or just enjoy them as a snack.