In a bowl, combine the ground beef with salt and black pepper. Form the mixture into 4 equal-sized patties.
In a hot skillet or on a grill, cook the patties for 2-3 minutes on each side. Set aside to cool slightly.
In a pan, sauté the chopped mushrooms, onion, and garlic in olive oil and butter until most of the moisture has evaporated.
Cut the puff pastry into four equal-sized squares. Place a spoonful of the mushroom mixture in the center of each square.
Spread Dijon mustard on top of each burger patty, then place them on top of the mushroom mixture.
Fold the puff pastry over the filling, ensuring the edges are well sealed to prevent them from opening during baking.
Brush the top of each pastry-wrapped burger with a beaten egg to achieve a beautiful golden-brown finish.
Place the wrapped burgers on a baking sheet lined with parchment paper and bake at 400°F (200°C) for approximately 20-25 minutes, or until the pastry is golden brown and crispy.
Let cool for a few minutes before serving with a fresh salad or roasted potatoes.
To provide the best experiences, we and our partners use technologies like cookies to store and/or access device information. Consenting to these technologies will allow us and our partners to process personal data such as browsing behavior or unique IDs on this site and show (non-) personalized ads. Not consenting or withdrawing consent, may adversely affect certain features and functions.
Click below to consent to the above or make granular choices. Your choices will be applied to this site only. You can change your settings at any time, including withdrawing your consent, by using the toggles on the Cookie Policy, or by clicking on the manage consent button at the bottom of the screen.