Crispy Smashed Potatoes with Truffle Mustard Crème Fraîche & Smoked Fleur de Sel

At the Lello table

The pleasure of a smashed potato is almost entirely structural: a creamy center held beneath an irregular, brittle crust. Here, cool crème fraîche is sharpened with Périgord truffle mustard, while smoked fleur de sel is added only at the table so its smoke and delicate crystals remain intact.

Method

1. Heat the oven to 450°F / 230°C. Place a heavy rimmed baking sheet in the oven for 8 to 10 minutes so the potatoes meet a genuinely hot surface.
2. Place the potatoes in a saucepan, cover generously with cold water and add the coarse sea salt. Bring to a boil, reduce to a steady simmer and cook for approximately 15 to 18 minutes, until a thin knife enters the center with little resistance but the potatoes remain intact.
3. Drain and allow the potatoes to steam-dry in the colander for 5 minutes. Surface moisture is the enemy of crispness.
4. Place each potato on a board and press gently with the bottom of a glass or small plate until approximately ½ inch / 1.25 cm thick. Keep the pieces irregular; the cracks become the crispest parts.
5. Carefully remove the hot baking sheet. Arrange the potatoes with space between them and brush or drizzle generously with the olive oil. Season with black pepper. Roast for approximately 25 to 30 minutes, until deeply golden and crisp at the edges. Turn once after about 18 minutes if the underside is browning more quickly than the top.
6. While the potatoes roast, stir together the crème fraîche, Périgord truffle mustard, lemon juice and half of the chives. Do not add substantial salt; both the mustard and finishing salt will complete the seasoning.
7. Swoop some of the truffle-mustard crème fraîche across a serving platter, leaving part of the surface exposed. Arrange the hot potatoes partly over and partly beside the sauce so several edges remain completely crisp.
8. Scatter with the smoked fleur de sel and remaining chives immediately before serving.

Cook’s notes

• Keep the truffle cool and the smoke uncooked. Both featured ingredients are more expressive when protected from prolonged heat.
• The Périgord truffle mustard is folded into cool crème fraîche rather than roasted on the potatoes; the mustard retains its acidity and the truffle remains aromatic.
• The smoked fleur de sel belongs only at the end. Heating it into the dish would dissolve its crystals and flatten the subtle smoke that makes it worth using.

Substitutions

• Fingerling or small red potatoes work well. Avoid very large russets; their floury texture and size make them more difficult to smash neatly.
• Full-fat sour cream is the closest substitute for crème fraîche. Greek yogurt works but produces a noticeably tangier sauce.
• Classic Dijon can replace the truffle mustard with only a few drops of good truffle oil. Do not pour heavily; the result should still taste like mustard and potato, not perfume.
• Plain fleur de sel may replace the smoked version. Do not compensate with liquid smoke.
• Flat-leaf parsley can replace chives, although it changes the dish from oniony freshness toward a greener herb finish.

To serve

Excellent alongside steak, roast chicken or a simple green salad. For brunch, serve with softly scrambled eggs. For cocktails, make the potatoes smaller and offer the truffle crème fraîche on the side as a dipping sauce.

Storage & make-ahead

The crème fraîche mixture can be prepared up to 2 days ahead and kept refrigerated. The potatoes are best immediately after roasting. Re-crisp leftovers at 425°F / 220°C for 8 to 10 minutes, keeping leftover sauce separate so the potatoes do not soften in storage.