Clean mushrooms if necessary, but make sure they are dry. Then, finely chop the mushrooms (or pulse in a food processor). Chop shallots and thyme leaves. Mince garlic.

Heat your sauté pan or cast-iron skillet to a medium heat and add olive oil. Sauté shallots and garlic until translucent. Add mushrooms, season with salt and pepper. Cook until all the liquid has evaporated (about ⅔ of the way in add Thyme). You can see from images and video they will be dark colored, and no liquid remains. Place this in a bowl and set in refrigerator to cool.

Using butcher's twine, tie the tenderloin in multiple areas to create a more even cylindrical shape. This will allow for a more even cook. I did not do this, but I would if I was using a cut of beef that was a little bigger piece of meat. But I do recommend. Pre-heat skillet to medium high.

Season your Venison with Salt and Pepper and then add in oil into your skillet and sear the Venison on all sides including the top and bottom just to get a golden-brown crust. Remember you are not really cooking the meat just searing it. Remove from skillet and using a baking dish or plate coat the meat with Dijon mustard and be sure to coat it very well. Set aside while we start on the prosciutto and Duxelle mixture.

Lay out multiple overlapping pieces of plastic wrap approximately 2 feet long on your countertop. Lay down 6 overlapping pieces of prosciutto being careful not to rip the slices. You want the prosciutto to be able to wrap entirely around the Wellington and extend at least 2 inches beyond each end. Using a spatula, place that duxelles mixture on top of the prosciutto spreading it around leaving about 1 to 1 ½ inches from the edge.

Place Venison Tenderloin on top of duxelles. Using the back side of the plastic wrap, fold over and repeat process on the front ensuring you get a tight roll from front to back and repeat process on the side. Place in the refrigerator for 30 minutes.

Flour your surface and unwrap your puff pastry. Gently roll it out to thin it. You’re looking for ⅓’ thick. Prepare egg wash by whisking two eggs in a bowl.

Preheat oven to 425°F. To make your lattice, gently roll out your second pastry sheet. Use lattice cutter to shape pastry. Egg wash your Wellington very well and then cover with the lattice. Place Wellington on parchment paper and insert your Meater Plus Meat Probe inside Wellington to track temperature and salt just before it goes into the preheated oven.

Bake until internal temperature reaches 115°F. Remove from oven and let it rest for 20 minutes before making 1” slices into the Venison Wellington.