Duck Fat, Josper Roasted Potatoes Recipe

Prep and Parboil

Preheat a Josper or high-temperature oven/grill to 230–260°C (450–500°F). Wash the potatoes; leave skins on. If potatoes are larger than bite-size, halve or quarter so pieces are roughly uniform (about 2–3 cm). Place potatoes in a large pot, cover with cold salted water, bring to a simmer and cook until just tender when pierced (8–12 minutes depending on size). Drain well and let steam-dry in the colander for 5 minutes.

Rough the Edges

Return the drained potatoes to the pot. Shake the covered pot a few times over the burner (low heat) or toss gently to rough the surfaces — this creates extra crispness when roasted.

Coat with Duck Fat

In a small saucepan, warm the duck fat until liquefied. Toss the potatoes with warm duck fat, 1 tablespoon olive oil, 1 tsp sea salt and the black pepper so they are evenly coated. Add thyme sprigs if using.

Roast in Josper

Spread potatoes in a single layer on a heavy-duty perforated tray or cast-iron pan suitable for the Josper. Roast at high heat (Josper: 230–260°C with charcoal/wood smoke) for 20–30 minutes, turning once or twice until deeply golden and crisp on the exterior. If using a conventional oven, roast at 230°C (450°F) for 35–45 minutes, turning halfway. Total crisp time may vary.

Finish

Transfer roasted potatoes to a bowl lined with paper towel for a minute to absorb any excess fat. Season immediately with flaky sea salt. Keep warm while finishing other components.

Sweat the Onions

Melt the butter (or dairy-free butter with 1 tsp neutral oil) in a wide sauté pan over medium-low heat. Add the finely diced yellow onions and minced shallot. Cook gently, stirring often, until the onions are very soft, translucent and beginning to caramelize lightly, about 25–35 minutes. Do not rush or brown too darkly; the goal is sweet, silky onions.

Add Garlic and Deglaze

Add the minced garlic and cook 1 minute more. Increase heat to medium and add the warm stock to deglaze, scraping any fond from the pan. Simmer gently until the liquid has mostly reduced and the mixture is soft and cohesive, about 6–8 minutes.

Blend to a Purée

Transfer the onion mixture to a blender or use an immersion blender. Add the cream (or coconut cream for DFO) and blend until completely smooth and silky. If needed, pass through a fine-mesh sieve for extra smoothness. Return to a clean saucepan and warm gently — do not boil.

Season and Finish

Stir in grated nutmeg, salt and white pepper. Adjust seasoning to taste. Keep warm on very low heat until serving; if too thick, whisk in a tablespoon or two of warm stock to reach desired saucy consistency.

Prepare Oil and Shallots

Dry the thinly sliced shallots thoroughly by spreading them on a clean towel and patting off moisture — excess water will cause oil spatter. Pour neutral oil into a wide, heavy saucepan or fryer to a depth of about 2.5 cm (1 inch). Heat oil to 175°C (350°F).

Fry in Batches

Fry the shallots in small batches so they have room to move and the oil temperature remains steady. Fry until golden brown and crisp, about 2–4 minutes per batch. Use a slotted spoon to remove the shallots and place them on a rack or paper towel-lined tray to drain. Sprinkle immediately with fine sea salt.

Double-Fry Option (for Extra Crispness)

For an extra-crisp result, fry batches once at 150–160°C (300–320°F) until pale and soft (about 2 minutes), drain briefly, then raise oil to 180–190°C (355–375°F) and fry again until golden and crunchy. Drain and salt.

Store Briefly

Allow crispy shallots to cool completely before using; they will crisp further as they cool. Use immediately for best texture.

Spoon a generous pool (about 2–3 tablespoons) of warm soubise onto each plate. Nestle a portion of Josper roasted potatoes (about 200 g per serving) on top or alongside the sauce. Scatter crispy shallots over the potatoes and sauce for crunch. Sprinkle chopped parsley, a little lemon zest and a pinch of flaky sea salt as a final garnish. Serve immediately while potatoes are hot and crisp.