Roasted porcini and potatoes recipe, staggered on the tray

This roasted porcini and potatoes recipe solves a problem most cooks solve badly: potatoes need dry heat to crisp, and porcini release water the moment they hit a hot pan.

Chef Gianluca Deiana Abis of Zafferano & Co. gets around it by roasting the two components in stages on one sheet pan, giving the potatoes time to seal before the mushrooms' moisture ever reaches them. The result is a simple autumn side dish that depends more on timing than on technique most home cooks don't already have.

Ingredients

Potatoes want dry heat to crisp. Porcini release water the moment they hit the pan. Stagger the two and neither one ruins the other.

• 700 g Yukon Gold or other waxy-floury potatoes, peeled and cut into 3 cm chunks
• 5 tbsp extra virgin olive oil, divided
• 1 tsp fine sea salt, plus more for the porcini
• Black pepper, to taste
• 450 g fresh porcini, brushed clean (not washed)
• 3 garlic cloves, crushed
• 6 sprigs fresh thyme
• 1 small sprig fresh rosemary
• 2 tbsp dry white wine (optional)
• 2 tbsp flat-leaf parsley, chopped
• Flaky sea salt, to finish

Method

1. Slice the porcini lengthwise through cap and stem into 1 cm pieces, keeping flat cut faces intact; they brown better than ragged ones. Do not wash them, since wet porcini steam instead of colouring.
2. Rinse the cut potatoes to wash off surface starch, then dry them thoroughly with a towel. A drier surface means a crisper crust.
3. Warm 2 tbsp of the oil in a small pan with the garlic, thyme and rosemary over low heat for 5 minutes, just until fragrant, then strain and set aside. This infuses the oil without frying the herbs bitter.
4. Heat the oven to 220°C with a heavy sheet pan inside for 20 minutes, so the tray itself is hot enough to sear on contact.
5. Toss the potatoes with 3 tbsp oil, the salt and pepper. Spread them on the hot tray in a single layer and roast for 25 minutes untouched, then turn each piece once.
6. Only now toss the porcini with the remaining oil and a pinch of salt; salting them earlier draws out water before they ever reach the oven. Lay them cut-side down on the cleared half of the tray and roast 15-18 minutes, until the liquid they release has evaporated and the cut faces have browned.
7. Pour the strained herb oil over both, discarding the solids but keeping a few thyme leaves. Add the wine if using, scraping up the browned bits as it hisses away, then fold everything together gently with two spatulas, since porcini break easily. Return to the oven for 3 minutes to heat through.

Serve it while the crust still holds

Spoon the potatoes and porcini from underneath so the crisp faces stay upward, and get them to the table within three or four minutes of leaving the oven; the crust softens fast once it's plated. Finish at the table with a thread of raw olive oil and flaky salt rather than pepper stirred in earlier, since roasting kills the aroma that raw pepper still carries.

A glass of Nebbiolo d'Alba or a low-tannin Alto Adige Pinot Nero both suit the dish's woodland notes; for readers building a full porcini menu, this pairs well before or after our tagliatelle ai porcini recipe without repeating the same texture twice.

Can this be made with other mushrooms? Chestnut or portobello mushrooms roast well on the same timing, though neither matches the depth porcini give once the pan juices reduce.