Tournedos de Boeuf with Pommes Soufflées and Classic Béarnaise

⏱ 90 min · Serves 4

The grand old trio of the French dining room: thick-cut fillet steaks seared in foaming butter, a tarragon-scented béarnaise whisked to velvet, and potato slices that puff into crisp golden pillows in two baths of hot oil. It takes nerve and a thermometer, but nothing on a plate looks more triumphant.

Per serving: 965 kcal · 45.0g protein · 34.0g carbs · 72.0g fat

Ingredients

• 4 beef fillet tournedos, 180g each and 4cm thick, tied with string
• 2 tbsp neutral oil, for searing
• 40g unsalted butter, plus 20g for basting
• 2 garlic cloves, lightly crushed
• 2 sprigs thyme
• Flaky sea salt and coarsely ground black pepper
• For the pommes soufflées:
• 900g large, mature, waxy-ish potatoes (Desiree or Maris Piper), peeled
• 2 litres groundnut or sunflower oil, for frying
• Fine salt, to finish
• For the béarnaise:
• 3 tbsp white wine vinegar
• 3 tbsp dry white wine
• 2 shallots, very finely chopped
• 1 tbsp tarragon stalks, chopped
• 6 black peppercorns, crushed
• 3 large egg yolks
• 200g unsalted butter, clarified and kept warm
• 2 tbsp tarragon leaves, chopped
• 1 tbsp chervil or flat-leaf parsley, chopped
• Squeeze of lemon juice
• To serve: watercress and 1 tsp red wine vinegar

Method

1. Trim the potatoes into neat cylinders, then slice lengthways on a mandoline to exactly 3mm — even thickness is what makes them puff. Rinse well in cold water to remove surface starch, then dry thoroughly between tea towels.
2. Set two pans of oil: one at 150C, one at 190C. Working in small batches, lower slices into the 150C oil and swirl the pan constantly for 4–5 minutes until they are pale, blistered and floppy with a faint bubble forming. Lift onto kitchen paper and leave to cool for at least 15 minutes (they can wait an hour).
3. Make the béarnaise reduction: simmer vinegar, wine, shallots, tarragon stalks and peppercorns until reduced to about 2 tbsp. Strain and cool slightly.
4. Whisk the yolks with the reduction in a bowl over barely simmering water until thick, pale and ribboning, about 3 minutes. Off the heat, trickle in the warm clarified butter, whisking constantly, until glossy and thick. Fold in tarragon and chervil, season, add lemon. Keep somewhere warm — not hot — with cling film on the surface.
5. Season the tournedos generously. Heat oil in a heavy pan until just smoking and sear 2½–3 minutes per side for rare-to-medium-rare. Add butter, garlic and thyme, baste for 1 minute, then rest on a warm plate for 8 minutes. Snip off the string.
6. While the steaks rest, return the cooled potato slices to the 190C oil, a handful at a time. They will inflate into puffed pillows within 30–60 seconds; fry until deep gold and crisp, drain and salt immediately.
7. Plate each tournedos with a mound of pommes soufflées, a spoonful of béarnaise alongside (and the rest in a warm jug), and a small tangle of watercress dressed with red wine vinegar. Serve at once.