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

1. Preheat Oven: Preheat your oven to 400°F (200°C).
2. Sauté Mushrooms: In a skillet, heat olive oil over medium heat. Add the chopped mushrooms, thyme, salt, and pepper. Sauté until the mushrooms are browned and the moisture has evaporated, about 5-7 minutes. Remove from heat and let cool.
3. Cook Beef: In the same skillet, add the beef cubes and sear them for about 2-3 minutes until browned but not cooked through. Remove from heat and allow to cool.
4. Combine Ingredients: In a bowl, mix the cooled mushrooms with the beef and Dijon mustard. Ensure everything is evenly combined.
5. Roll Out Pastry: On a floured surface, roll out the puff pastry to about 1/8-inch thickness.
6. Cut Pastry: Cut the pastry into squares, approximately 4 inches each side.
7. Fill Pastry: Place a spoonful of the beef mixture in the center of each pastry square.
8. Seal Wellingtons: Fold the pastry over the filling to create a triangle or rectangle, pressing the edges to seal. You can crimp the edges for a more decorative look.
9. Egg Wash: Place the sealed Wellingtons on a baking sheet lined with parchment paper. Brush the tops with the beaten egg for a golden finish.
10. Bake: Bake in the preheated oven for about 25-30 minutes or until the pastry is golden brown and puffed.
11. Cool and Serve: Allow the Mini Beef Wellingtons to cool slightly before serving.

With these straightforward steps, you’ll have a beautiful batch of Mini Beef Wellingtons ready to impress!