📖 Instructions

1. Preheat your oven to 400°F (200°C). Make sure your oven is fully preheated before you start, it's crucial for a perfectly cooked Wellington!
2. Pat your beef tenderloin dry with paper towels. Season generously with salt and pepper. Trust me, don't skimp on the seasoning!
3. Prepare the duxelles: Finely chop 1 pound of mushrooms. In a large pan, sauté the mushrooms over medium heat until all the moisture has evaporated and they're deeply browned. Season with salt, pepper, and a dash of thyme. Let it cool completely. Don't rush this step; cool duxelles are key to preventing a soggy Wellington!
4. Lay out a large sheet of plastic wrap. On the plastic wrap, spread out a thin layer of the cooled duxelles, forming a rectangle slightly larger than the beef tenderloin.
5. Place the beef tenderloin on top of the duxelles. Spread a thin layer of Dijon mustard over the beef. This adds a wonderful tangy flavor!
6. Wrap the beef tightly in the plastic wrap, rolling it into a log-like shape. Twist the ends tightly to seal. Refrigerate for at least 30 minutes to firm up—this makes it way easier to handle when wrapping in pastry.
7. Unroll and remove the plastic wrap. Spread a layer of high-quality puff pastry over a lightly floured surface. (If using store-bought, make sure to follow its thawing instructions carefully.)
8. Place the beef on the center of the pastry. Fold the pastry over the beef, and tightly seal the edges. Crimp the edges to create a decorative seal. If you're feeling creative, you can even make decorative cuts in the pastry.
9. Brush the pastry with an egg wash (1 egg beaten with a tablespoon of milk or cream). This gives a beautiful golden-brown finish, my personal favorite part of the cooking process.
10. Bake for 30–40 minutes, or until the pastry is golden brown and the internal temperature of the beef reaches 130-135°F (54-57°C) for medium-rare. Use a meat thermometer to check the doneness; this is super important to prevent undercooking!
11. Once cooked, remove from the oven and let rest for at least 15-20 minutes before slicing and serving. This allows the juices to redistribute throughout the meat, making it incredibly tender and flavorful.
12. Slice and serve immediately. Garnish with fresh herbs like parsley and thyme and a drizzle of red wine reduction (optional, but highly recommended!). Enjoy your culinary masterpiece!