01 -
Dice the onion and chop the mushrooms into small pieces.
02 -
Warm the olive oil in a big frying pan over medium heat. Toss in the onion and cook until soft and see-through—takes about 3 or 4 minutes.
03 -
Add the chopped mushrooms to the hot pan. Stir as they cook, letting their liquid come out for 5-7 minutes until they've softened completely.
04 -
Stir in mayo, garlic, Parmesan, salt, and pepper until the mixture blends well.
05 -
Spread each pastry sheet into a rectangle about 30 x 40 cm (12 x 16 inches).
06 -
Evenly divide the mushroom mixture, spreading a thin amount across both pastry rectangles.
07 -
Scatter the shredded mozzarella across the mushroom layer on both sheets evenly.
08 -
Starting from the wider edge, roll each pastry tightly into a log shape.
09 -
Lay parchment paper on a baking tray. Place the rolled pastries on the tray and brush them all over with the beaten egg.
10 -
Use a sharp knife to cut each roll into 1 inch (2.5 cm) thick pieces. Lay the pieces flat on the parchment with a bit of space between them.
11 -
In a preheated oven set to 185°C (365°F), bake for 30 to 40 minutes or until the pastries puff up and turn golden.
12 -
Give the baked pinwheels 5 minutes to sit before you serve them. They'll taste best like this.