Preheat the oven to 200°C (400°F). If the pan you're using isn't oven-safe, set aside a baking dish.
Heat a large frying pan over medium high heat. Once the pan is hot, add the olive oil and mushrooms.
2 teaspoons olive oil, 700 grams mixed fresh mushrooms
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, 1/2 teaspoon sea salt, 1/2 teaspoon black pepper, 1/4 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 dry white wine
Add the water or broth and bring to a low boil.
300 ml 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.