Steak Sandwich with Entrecôte Sauce

Directions

• For the entrecôte sauce:
• Melt 1/4 of the butter in a saucepan over medium heat.
• Add the shallots, anchovies, nutmeg, salt, and pepper. Cook, stirring, until shallots are soft and translucent. Use a wooden spoon to break up the anchovies.
• Turn off the heat and let the mixture sit for 5 minutes.
• Keeping the heat off, add the remaining butter and stir occasionally until fully melted. Set aside and let cool to room temperature.
• In a blender, combine the egg yolk, mustard, capers, lemon juice, Worcestershire sauce, basil, and parsley.
• Start blending on low speed. Gradually pour in the cooled butter and shallot mixture while blending slowly to help it emulsify.
• If the sauce becomes too thick, add a small splash of room temperature water to loosen it. The sauce should be pourable, like slightly thickened cream.
• Taste and add salt if needed. Keep the sauce warm or serve immediately.
• For the onions:
• Heat a pan or grill over medium-low heat and add olive oil or butter.
• Add the onions and a pinch of salt. Cook slowly, stirring every few minutes.
• After about 10 minutes, the onions will soften. Lower the heat if they start browning too fast.
• Continue cooking and stirring for about 25 minutes or until onions are golden, soft, and sticky. Remove from heat and set aside.
• For the steak:
• Bring steaks to room temperature and pat dry.
• Season generously with salt and pepper.
• Heat a heavy pan or grill on high. Add a drizzle of olive oil.
• Cook steaks for 2–3 minutes per side for medium-rare, or cook to your preferred doneness.
• Rest steaks for 5 minutes before slicing.
• Assemble the sandwich:
• Toast the ciabatta halves in a pan or grill.
• Slice the steak thinly against the grain.
• Spread a generous layer of entrecôte sauce on the bottom half of the bread.
• Add the steak slices, a handful of rocket, and caramelised onions.
• Drizzle more sauce on top, then close the sandwich with the other half of the bread. Enjoy!