Place the porcini mushrooms in a small bowl, add the boiling water, and let them rehydrate.
10 g dried porcini mushrooms, 100 ml boiling water
Shred the tofu using the large holes on a box grater.
320 g extra firm tofu
Heat the olive oil in a large frying pan over medium heat. Add the diced onion and minced garlic, cooking until softened. Stir in the brown sugar and balsamic vinegar, reduce heat, and cook for an additional 5 minutes until lightly caramelised, stirring often.
Increase the heat slightly and add the chopped chestnut mushrooms. Cook for around 2 minutes, or until the mushrooms begin to release their moisture.
250 g chestnut mushrooms
Add the rehydrated porcini mushrooms to the pan, then pour in the soaking water through a fine mesh sieve to catch any grit. Add the tofu, raisins, dark soy sauce, marmite, fresh thyme, sage, parsley, onion powder, salt and pepper. Simmer until all the liquid evaporates from the pan.
20 g raisins, 2 tablespoon dark soy sauce, 1 tablespoon Marmite , 4 sprigs fresh thyme, 1 teaspoon dried sage, 1 teaspoon dried parsley, 1 teaspoon onion powder, ½ teaspoon fine sea salt, ½ teaspoon ground black pepper
Transfer the mixture to a large plate or baking sheet to cool down. Once cooled, transfer it to a food processor and add the oat flour and miso paste. Pulse until it resembles a rough, chunky paste. Transfer the mixture back to the plate or baking sheet and chill in the fridge for at least 30 minutes.
2 tablespoon oat flour, 1 tablespoon miso paste
Preheat the oven to 200°C (390f) (fan) and line a large baking sheet with baking parchment.
Remove the pastry from the fridge to come to room temperature. Unroll it on a clean work surface and cut it into 8 equal rectangles. Brush each rectangle with dijon mustard.
475 g puff pastry, 2 tablespoon dijon mustard
Divide the chilled filling equally between each rectangle, forming it into a mound slightly off-centre. Fold the pastry over the filling and crimp the edges with a fork to seal. Make 5 diagonal slits on top of each roll for steam to escape.
In a small bowl, mix together the ingredients for the egg wash. Brush half of the wash over the tops of the sausage rolls. Place the rolls on the prepared baking sheet and bake for 25–30 minutes, or until golden and flaky.
Remove from the oven and gently brush the tops again with the remaining egg wash. Allow to cool for 10–15 minutes before serving. Alternatively, cool completely and store in an airtight container for later.
Notes
Note 1: I use chestnut mushrooms in this recipe. This is the name we give to standard brown mushrooms in the UK. I believe in the USA and Canada these are called cremini mushrooms. You can be fairly flexible with which mushrooms you use however. For a meatier taste, try using some fresh shiitake too!Note 2: Marmite (very popular in the UK) is a type of yeast extract with an incredibly strong, meaty flavour. If you can't get it, feel free to use any jarred yeast or vegetable extract. If you can't find this either, substitute for 2 tablespoon nutritional yeast flakes. Note 3: I use oat flour in this recipe not for it's gluten free nature (since we're already using other gluten ingredients elsewhere in the recipe) but rather because I like how it affects the texture of the filling. It binds the ingredients together without making them into a gluey, sticky dough. You can easily replace it with plain white flour/all purpose flour and I doubt you'll notice a difference, but Oat flour is my favourite pick for this recipe.Note 4: Unfortunately, not all store-bought puff pastry is vegan. However most here in the UK are, unless stated otherwise. Be sure to check the ingredients though - and remember, just because it doesn't say "suitable for vegans" doesn't mean it's not vegan!