1. Preheat the oven to 180°C/350°F/gas 4.
2. The fun and unique part of this side dish is that you need to slice multiple times through the potatoes, but – importantly – without going all the way through, giving you a kind of concertina-style potato. This looks beautiful but also makes them wonderfully absorbent of flavour and amplifies their crispiness. Try to choose small potatoes, give them a wash, and if you have any larger ones, cut them in half and use the flat side as a base.
3. To make this process as simple as possible, place a potato on a board between the handles of two wooden spoons, so that when you slice down into the potato the spoons stop the blade from going all the way through.
4. Carefully slice at just under ½cm intervals all the way along. Repeat with all the potatoes, placing them in a large roasting tray as you go.
5. Pick half the thyme leaves into a pestle and mortar and pound with the turkey dripping or oil. Spoon over the potatoes, making sure the fat gets down into the cuts you’ve made, then season with sea salt and black pepper.
6. Roast for 1 hour, or until the potatoes are golden and tender.
7. Meanwhile, tear the bread into a baking dish, add the hazelnuts and toast in the oven for 10 minutes. Remove and allow to cool, then tip into a food processor, strip in most of the remaining thyme leaves, add a pinch of sea salt and black pepper and half the cheese, and pulse into coarse crumbs.
8. When the hour is up, sprinkle the crumbs over the potatoes, then finely crumble a little bit of the remaining blue cheese on to each one.
9. Dress the rest of the thyme sprigs with a tiny bit of oil and sprinkle randomly on top. Return to the oven for a final 10 minutes, or until the cheese starts to melt, then serve.

For a tasty kitchen shortcut, check out Jamie's Hasselback Potatoes from his new frozen range!