Creating Mini Beef Wellington Bites can be fun and straightforward if you follow these simple steps:

1. Preheat Your Oven: Make sure to preheat your oven to 400°F (200°C).
2. Sear the Beef: In a skillet over medium-high heat, add olive oil. Season the beef fillet with salt and pepper. Sear for 2-3 minutes on each side until browned. Remove from heat and let it cool slightly.
3. Prepare the Mushroom Mixture: In the same skillet, add the finely chopped mushrooms and garlic. Cook until the mushrooms are golden and all the moisture has evaporated. Add thyme, season with salt and pepper, and let it cool.
4. Coat the Beef: Once the beef is cool, brush the Dijon mustard over the entire surface.
5. Roll Out the Pastry: On a floured surface, roll out the puff pastry until it’s about 1/8 inch thick. Cut it into squares large enough to envelop each piece of beef.
6. Assemble the Bites: If using prosciutto, place a slice on top of the mustard-brushed beef. Spoon the mushroom mixture over the beef. Wrap the puff pastry around the beef, sealing the edges with the beaten egg.
7. Place on Baking Sheet: Transfer the wrapped beef bites to a lined baking sheet. Brush each with the egg wash for a golden finish.
8. Bake: Bake in the preheated oven for 25-30 minutes until puffed and golden brown.
9. Rest the Bites: Remove from the oven and let cool for about 10 minutes before serving.

These steps will ensure you create delightful Mini Beef Wellington Bites easily.