1. Season the beef tenderloin generously with salt and black pepper. Heat 2 tbsp of olive oil in a large pan over high heat. Sear the beef on all sides until browned, about 2-3 minutes per side. Remove from the pan and set aside to cool.
2. Brush the seared beef tenderloin with Dijon mustard, and let it rest while prepping the mushroom duxelles.
3. In the same pan, add 2 tbsp of unsalted butter over medium heat. Sauté the minced shallots and garlic until fragrant, about 2 minutes.
4. Add the finely chopped mushrooms and cook until they release their moisture and become dry, about 10 minutes. Stir in the fresh thyme leaves and deglaze the pan with 1/4 cup of dry white wine. Cook until the wine evaporates. Remove from heat and allow to cool.

1. Lay out cling film on a flat surface. Arrange the prosciutto slices on the film, slightly overlapping, to form a rectangle.
2. Spread the mushroom duxelles evenly over the prosciutto layer.
3. Place the beef tenderloin on the mushroom-covered prosciutto. Using the cling film, carefully roll the prosciutto around the beef, ensuring it is tightly wrapped. Chill in the refrigerator for 15 minutes.
4. Roll out the puff pastry on a lightly floured surface. Unwrap the beef from the cling film and place it on the pastry. Brush the edges of the pastry with beaten egg.
5. Fold the pastry over the beef, sealing the edges well. Trim any excess pastry and brush the entire surface with the beaten egg. Chill for 10 minutes.

1. Preheat the oven to 400°F (200°C). Place the wrapped beef on a baking sheet lined with parchment paper. Bake for 25-30 minutes or until the pastry is golden brown.
2. Meanwhile, make the Madeira sauce. In a saucepan, heat 1 tbsp olive oil over medium heat. Sauté the chopped shallot and minced garlic until soft.
3. Add 1 cup of Madeira wine, and bring to a boil. Reduce the mixture by half, then add 1 cup of beef stock and simmer until slightly thickened.
4. Whisk in 2 tbsp of unsalted butter until the sauce is glossy. Stir in chopped fresh parsley, and season with salt and pepper to taste.

1. Let the Beef Wellington rest for 10 minutes before slicing. Serve with a generous drizzle of Madeira sauce on top. Enjoy your sophisticated American main course with a delightful blend of flavors and textures.