Blender Béarnaise Sauce
Make the chips
- Preheat oven to 200C. Cut the unpeeled potatoes into finger-sized chips. Place cut potatoes in a large saucepan. Cover with cold water. Bring to the boil over high heat. Reduce heat to medium. Boil for 2 mins or until almost tender. Drain well.
- Put the chips among 2 large baking paper-lined oven trays in a single layer and dry in oven for 10 mins. Remove from oven and toss with duck fat or olive oil and season with sea salt and pepper. Spread chips in a single layer – use two-three trays rather than overcrowd.
- Roast for 20-30 mins, turning if necessary until golden and crisp. Season with salt.
Make the Béarnaise
- Boil wine, vinegar, ecshallot, peppercorns, tarragon and chervil sprigs and a pinch of salt in a medium saucepan for 3 mins or until reduced by about two-thirds. Strain liquid through a fine sieve into a small bowl.
- Combine 3 tbs vinegar reduction, egg yolks, and a pinch of salt in the base of a stick blender jug (the jug and blender need to be a tight fit).
- Meanwhile, melt ghee in a small saucepan over high heat. Transfer hot ghee to a heatproof jug. Place the stick blender into the base of the jug and turn it on. With the blender constantly running, slowly pour hot ghee into the jug. It should emulsify with the egg yolk and vinegar reduction. Continue pouring until all ghee is added. Sauce should be thick and creamy. Season to taste with salt. Fold in chopped tarragon and chervil. Serve immediately, or transfer to a thermos jug and keep warm for up to 1 hour before serving. Béarnaise cannot be cooled and reheated.
Cook the steaks
- Heat a barbecue grill plate until smoking hot. Season steaks and drizzle with oil, massage steaks. Grill, turning, until medium rare (4-6 minutes each side; internal temperature reads 58C on a meat thermometer). Rest in a warm place for 12 mins.
- Carve the steak and serve with chips, salads and béarnaise sauce to the side.
Tip: For 180g clarified butter, heat 250g butter over low heat until fat and milk solids separate, then strain off clear butter (discard milk solids).