What's Cooking: Beef Wellington

This week, Colin McKaharay, of Blackstone Steakhouse in Melville, shows Lily Stolzberg how to make beef Wellington.

Serves - 4 to 5 
Prep time - 60 minutes
Cook & Rest - 45 minutes
For the mushroom duxelle:
3 tablespoons olive oil
18-24 large chanterelle mushrooms (or any earthy mushroom), finely diced (about 4 cups)
Salt
Freshly ground black pepper
1 teaspoon thyme leaves
For the chive crepes:
2 eggs
1 cup flour, lightly packed and leveled
1 cup milk
1 teaspoon chopped chives
1 teaspoon fresh thyme
Pinch of salt
Nonstick cooking spray
Assembly of Wellington:
1 pound center cut beef tenderloin at room temperature
Salt
Freshly ground black pepper
1 tablespoon grapeseed oil
1 tablespoon Dijon mustard
4 slices Iberico ham
Sheet of puff pastry, thawed if frozen (Gluten-free tip: you can buy gluten-free puff pastry online.)
2 egg yolks
Mushroom duxelle:
Place a medium sauté pan over medium high heat. Add oil and when hot, add mushrooms. Season well with salt and pepper and add the thyme. Stirring frequently to be sure mushrooms don’t stick, cook until all the moisture has evaporated, about 10 minutes. Remove from heat and cool.
Chive Crepes:
In a large mixing bowl, combine eggs, flour, milk, chives, thyme and salt. Whisk until incorporated. Transfer to the refrigerator to rest for at least 30 minutes.
Lightly spray a 10-inch nonstick pan and place over low heat. Add 1/4 cup batter to the pan and swirl the pan so the batter spreads evenly along the bottom into a very thin pancake. Let it cook for 25 to 30 seconds until set, then using an offset spatula to lift one side, flip and cook on other side for just a few seconds. Move quickly because you don't want any browning to occur. Remove crepe to plate. Continue cooking until batter is finished, making about 5 crepes. Place a parchment square between so they don’t stick.
Assembly of beef Wellington:
Season beef liberally with salt and pepper on all sides. Use your hands to press salt and pepper in while rolling and shaping beef to be cylindrical.
Heat a heavy pan (steel or cast iron) and add grapeseed oil, then sear beef, cooking 60 seconds per side. Remove beef to sheet tray and pour the juices from the pan over it. 
While hot, brush Dijon mustard all over, and then let it rest. Layer pieces of plastic wrap overlapping each other on the cutting board.
Depending on the width of the tenderloin, take 2 to 3 pancakes and trim into squares the length of the tenderloin, then line them up vertically on the plastic.
Layer on the prosciutto slices. Spread the mushroom duxelle over the ham. Season with salt and pepper. Pour resting juices from the beef over the mushrooms, then place beef at the bottom of the crepe. Using the plastic wrap to lift as you pull the crepe over the beef, roll the beef up completely, smoothing plastic and twisting the ends to form a tight package.
Refrigerate for 20 minutes. Preheat convection oven to 425 degrees or non-convection to 450 degrees. Again layer pieces plastic wrap. Place puff pastry in center. 
Use a rolling pin or dowel to evenly roll it to 1/8 inch thick, trimming if necessary to fit beef. Unwrap beef and place on the pastry 1/3 of the way up. Lightly brush pastry with egg wash and season with salt and pepper. Lift the plastic wrap up and roll the pastry over the beef, until the edges meet, then massage the pastry, smoothing it evenly across and sealing the seam.
Twist the plastic taking the excess pastry with it, until pastry melts together, and cut off the ends. Unwrap the Wellington, discard the plastic and smooth the ends, then brush with egg wash. 
Use the back of a knife to gently score the Wellington and create a decorative pattern. Season with more salt, place on a parchment-lined tray. Refrigerate for 5 minutes. 
Place in the center of the oven and bake for 20-30 minutes, until golden brown. Remove and let rest for 10-15 minutes before slicing and serving.