1) Heat a saucepan over medium heat with a drizzle of olive oil. Gently cook mushrooms for 5 minutes, season lightly with salt and pepper. Add a splash of sherry and cook off. Add beef stock and water and simmer over low heat.
2) Whisk eggs in a bowl with a pinch of salt and a splash of water, about 2 teaspoons. Sprinkle the flour while you whisk and add a dash of freshly grated nutmeg.
3) Heat a drizzle of olive oil at a time in a small nonstick pan over medium-high heat. Add a small ladle of eggs to the pan and swirl it around. Flip the egg crepe after 30 to 40 seconds and cook for 15 to 20 seconds on the other side. Stack up the egg crepes and when you've made the last (there should be about 6 to 8 crepes), roll the crepes and slice into 2 1/2cm strips.
4) Divide the crepe strips evenly among four bowls.
Top with two tablespoons chopped chives, ladle the beef and mushroom over the top and serve immediately.