Gourmet Beef Wellington Turnovers

1.

Preheat your oven to 400°F (200°C) to ensure it's hot enough to cook the turnovers evenly.

2.

Heat olive oil and butter in a skillet over medium heat, then sauté mushrooms and onion until softened.

3.

Add beef tenderloin pieces to the skillet, cooking until browned on all sides but not fully cooked through.

4.

Roll out the puff pastry on a floured surface, then cut it into equal square pieces for wrapping.

5.

Place a spoonful of mushroom mixture and a piece of beef onto each pastry square, then fold over.

6.

Seal the edges of the pastry to ensure no filling can escape during baking, and brush with beaten egg.

7.

Arrange turnovers on a baking sheet, leaving space between each, and bake in preheated oven for 20-25 minutes.

8.

Check that the pastry is golden and puffed up, and serve the turnovers hot, optionally with a fresh salad.