Peel and quarter the onions, and peel the garlic clove. Add both to the mixing bowl and chop for 5 sec / speed 5.
20 g butter
Add the butter and sauté for 3 min / 120 °C / speed 1.
350 g cremini mushrooms
Meanwhile, brush off any dirt from the cremini mushrooms, trim the stem ends, and quarter or chop into smaller pieces depending on size.
Add the mushrooms to the mixing bowl with the onions and cook without the measuring cup inserted for 6 min / 100 °C / reverse direction / gentle stir setting.
1 tbsp parsley, salt
Towards the end of the cooking time, add the frozen parsley and a pinch of salt through the lid opening.
Transfer the mushrooms into a mesh strainer to drain off excess liquid (give them a gentle press if needed so your puff pastry stays crisp and flaky!).
Assembling and baking:
Preheat your oven to 200 °C (conventional top/bottom heat).
1 puff pastry sheet
Take the puff pastry sheet out of the fridge, unroll it onto its baking paper, and cut into 4 equal rectangles.
Spoon the drained mushroom filling onto the bottom half of each rectangle, and cut a few small slits in the top half using a sharp knife.
Fold the top half over the filling and crimp the edges firmly with a fork to seal them up nicely.
1 egg
Transfer the turnovers along with the baking paper onto a baking sheet. Whisk the egg and brush it over the tops.
Bake in the oven for 15 - 20 minutes until the puff pastry is beautifully puffed and golden brown. Whip up the sauce while they bake!
Making the balsamic crispy onion sauce:
1 onion, 1 garlic clove
For the sauce, peel and quarter the onion and peel the garlic. Place both into the mixing bowl and chop for 5 sec / speed 5. Scrape down the sides of the bowl with a spatula.
20 g oil
Add the oil and sauté for 2 min / 120 °C / speed 1.
15 g all-purpose flour
Dust the flour over the onion mixture and cook for 1 min 30 sec / 100 °C / speed 1 to cook off the raw flour taste.
Meanwhile, clean the mushrooms, trim the stem ends, and chop them into small pieces.
125 g water, 100 g heavy cream, 15 g tomato paste, 1-2 tbsp balsamic vinegar, ½ tsp vegetable broth, 50 g cremini mushrooms
Add the water, heavy cream, tomato paste, balsamic vinegar, vegetable broth, and mushrooms. Blend for 5 sec / speed 8, then bring to a boil for 6 min / 100 °C / speed 4.
2 tbsp crispy fried onions
Stir the crispy fried onions into the finished sauce for 10 sec / reverse direction / speed 2 so they retain a lovely crunch.
salt and black pepper
Season the sauce to taste with salt and pepper, and serve warm alongside your hot puff pastry turnovers.
Enjoy!
Notes
Pairs amazingly well with potato croquettes, roasted potatoes, dumplings, or Duchess potatoes.