Mushrooms are fried in a pan until they release water and the water evaporates again. Cream cheese is placed in a bowl, and the hot mushrooms are poured over and stirred into a cohesive mixture. Mustard and ham strips are added, and chives are cut in to taste.  

Puff pastry is rolled out on the table into a square. Nowadays, I always cheat and buy the one that's in a roll in the refrigerator section, as it fits the size perfectly.

The filling is spread in the middle of the pastry. The pastry is gathered and shaped into a roll. Use a little water to "glue" the seams. Here, I turned it over and pricked the surface to get an even ham roll and allow any steam to escape. Unfortunately, I didn't gather the pastry enough, so it opened at the bottom during baking. Some people try braiding by cutting strips from 2-3 cm from the filling and gathering these in the middle. It gives a nice result but is beyond my skill level.

Finally, it can be made as a pie where 2/3 of the puff pastry is spread in a pie dish and the rest of the pastry is placed on top, for example, in a pattern or just with some holes pricked in the middle.

Place in a 200 degrees Celsius (392 degrees Fahrenheit) hot oven for 10-15 minutes or until the surface is golden.