Crafting Mini Beef Wellingtons can be a joyous experience if you follow these straightforward steps:

1. Prepare the Beef: Season the beef tenderloin with salt and pepper. In a hot skillet, add olive oil and sear the beef for 2-3 minutes on each side until nicely browned. Remove and let it cool.
2. Make the Mushroom Filling: In the same skillet, add the chopped mushrooms and cook until all moisture has evaporated. Add garlic and thyme, cooking for an additional minute. Set aside to cool.
3. Prep the Puff Pastry: On a floured surface, roll out the puff pastry and cut it into squares (about 4×4 inches).
4. Assemble the Wellingtons: Spread a thin layer of Dijon mustard on each pastry square. Place a spoonful of the mushroom mixture in the center and top it with a slice of the cooled beef.
5. Wrap the Wellingtons: Fold the corners of the pastry over the filling, sealing it tightly. Ensure the seams are pinched well to keep the filling intact.
6. Egg Wash: Brush the tops of the wrapped Wellingtons with beaten egg for a beautiful golden finish.
7. Bake: Preheat your oven to 400°F (200°C). Place the Wellingtons on a parchment-lined baking sheet and bake for 25-30 minutes or until golden brown.
8. Cool and Serve: Once baked, allow the Wellingtons to cool slightly before serving.

These steps will guide you to create Mini Beef Wellingtons perfectly. The careful assembly ensures that each Wellington remains tender and flavorful while boasting that flaky crust we all adore!