Add 1 tbsp olive oil to a large skillet and sauté the onions, garlic, carrots and celery for 2 minutes
Add the mushrooms, herbs, vinegar, salt and pepper and cook for a further 5 minutes
Stir in the beans and breadcrumbs then mash to create a thick, chunky mixture that comes together like a dough. If it’s too wet, add more breadcrumbs, if it’s too dry, add a drop of water
Take out your pastry and lay it flat on a work surface, covering with a damp towel to keep it from drying out
Take two sheets at a time, brushing with a thin layer of the remaining olive oil, then layering with the next two sheets. Brush the last sheet with oil then add the filling in a long line, lengthways, moulding into a cylinder shape
Gather up the dough and roll into a long log, securing the ends with a small bit of olive oil. Trim the sides if needed
Transfer to a lined baking sheet and cook for 25 minutes until golden brown and crisp
Leave to cool slightly before slicing and serving. Enjoy!