In a large skillet, melt butter and cook shallots for 2-3 minutes.

Add garlic and cook for 30 seconds.

Add mushrooms, dried thyme, salt and pepper. Stir and cook for 3 minutes.

Pour in white wine and cook for 10 minutes. Mushrooms should have no excess moisture anymore. Transfer to a bowl and set aside.

Season beef fillets on both sides with salt and black pepper.

Drizzle olive oil in a hot pan over medium-high heat and sear the filets for 2 minutes on each side. Set aside on a plate and cool for a couple of minutes.

On clear wrap, shingle 3 slices of prosciutto so they are slightly touching. Spread half the mushroom mixture on top of the prosciutto.

Brush each piece of beef with dijon mustard on all sides.

Place beef on top of mushroom duxelles and carefully wrap the prosciutto around the filet until you have it rolled up. This is a little tricky so don't get discouraged.

Place in the refrigerator for 30 minutes to an hour to chill and set.

Roll out puff pastry sheet on a lightly floured surface and cut in half.

Carefully unwrap the plastic wrap from the prosciutto wrapped steak and then wrap the puff pastry around the prosciutto wrapped steak to create the Beef Wellington. You can also decorate the the Beef Wellington with extra scraps of the buff pastry.

Place on a parchment paper lined baking sheet and brush each with egg wash then sprinkle with flaky salt.

Bake in the oven at 425° for 20-25 minutes checking desired doneness with a meat thermometer and the puff pastry is golden brown.

Let rest for 10 minutes then enjoy!