Creating Mini Beef Wellingtons can be enjoyable and rewarding if you follow these straightforward steps:

1. Preheat the Oven: Start by preheating your oven to 400°F (200°C).
2. Sear the Beef: Heat the olive oil in a skillet over high heat. Season the tenderloin with salt and pepper. Sear for 2-3 minutes on each side until browned. Remove from heat and allow to cool.
3. Prepare the Mushrooms: In the same skillet, add the chopped mushrooms and cook over medium heat until the moisture has evaporated. Season with salt, pepper, and thyme or rosemary. Stir in the Dijon mustard. Remove from heat and let the mixture cool.
4. Roll Out Puff Pastry: On a lightly floured surface, roll out the puff pastry into a ¼-inch thick rectangle. Cut into squares large enough to encase the filling (about 4×4 inches).
5. Assemble the Wellingtons: Place a spoonful of the mushroom mixture in the center of each pastry square. If using, spread a thin layer of pâté over the beef. Place a piece of seared beef on top of the mushroom mixture.
6. Seal the Pastry: Fold the corners of the pastry over the filling, pinching to seal. Brush the edges with the beaten egg wash to help them stick.
7. Place on Baking Sheet: Arrange the sealed pastries on a parchment-lined baking sheet, ensuring they have space in between for even cooking.
8. Egg Wash: Brush the tops of the Wellingtons with the remaining egg wash for a golden finish.
9. Bake: Bake in the preheated oven for 25-30 minutes or until golden brown and puffed.
10. Rest: Allow them to rest for 10 minutes before serving to let the filling settle.

These simple steps will guide you toward creating amazing Mini Beef Wellingtons that will have everyone coming back for seconds!