Cook the mushrooms, stirring as little as possible, until golden brown and reduced in size, about 6-8 minutes.
Reduce the heat to medium and add the onion. Cook for another 2-3 minutes, until translucent.
1 medium onion
Add the carrots and cook for 2-3 minutes.
2 medium carrots
Add the garlic, herbs, salt, pepper, and paprika. Stir to cook through, about 30 seconds.
2 cloves garlic, 2 teaspoons fresh herbs, ½ teaspoon sea salt, ½ teaspoon black pepper, ¼ teaspoon paprika
Pour in the wine. This will deglaze the pan, lifting any darker pieces that may have stuck to the pan while cooking.
100 ml (⅓ cup) dry white wine
Add the water or broth and bring to a low boil.
300 ml (1 ¼ cups) water
Whisk the arrowroot flour into the 2 tablespoons of water. Add this to the boiling liquid in the pan and stir quickly to combine. The sauce should thicken.
1 tablespoon arrowroot flour + 1 tablespoon water
Remove from the heat and stir in the cashew cream cheese, if using.
3 tablespoons cashew cream cheese
Spoon the mushroom mixture onto a baking dish. Top with the puff pastry, and roll the edges underneath to create a tidy appearance. Cut a couple of slits in the top of the pastry for steam to escape.
1 package puff pastry
Bake for 22-24 minutes, or until the pastry is a dark golden colour and the filling is bubbling. Cool for five minutes before serving.