Step 1

Generously season the beef filet with salt and pepper on all sides. Heat a tablespoon of olive oil in a large pan on high heat Sear the filet on all sides until well browned. Allow the fillet to cool. Once cooled, brush all sides with Coleman’s yellow mustard and set aside.

Step 2

Then, make the mushroom duxelles. Puree the mushrooms in a food processor. Then cook the mixture in a sauté pan, allowing all moisture to be released. Once all of the moisture has boiled off, set the pan aside to cool.

Step 3

Next, roll out a large piece of plastic wrap. Lay out the slices of prosciutto and spread the mushroom duxelles on top. Place the beef fillet in the middle, rolling the mushroom and prosciutto over the fillet. Use the plastic wrap to roll into a tight barrel shape and refrigerate for 20 minutes.

Step 4

Meanwhile, preheat the oven to 400F. While the oven is preheating, lightly flour your surface and roll out a sheet of puff pastry to a size that will wrap around the fillet. Unwrap the filet from the plastic and place in the middle of the puff pastry. Brush the edges of the pastry with the beaten egg yolks. Fold the pastry around the fillet, cutting off any excess pastry. Brush with beaten egg yolks and chill for 10 minutes. Place the fillet on a baking pan, brush again with beaten eggs. Score the top of the pastry without going all the way through and sprinkle with coarse sea salt. Bake at 400F for 25-35 minutes or until medium rare. Allow to rest for 10 minute before slicing and serving.