Pre-heat your oven to 180 C / 350 F / gas mark 4.
In a large frying pan, heat the oil then add the diced carrot. Cook for 5 minutes until just starting to soften.
Add the leeks and mushrooms to the pan and cook for another 5 - 10 minutes until the carrots, leeks and mushrooms are all cooked.
Next add the garlic and cook until releit releasessing its aroma.
Add the flour to the pan and stir so all of the ingredients are coated.
Pour in the cream and mix well so there are no lumps of flour.
Crumble in the stock cube and add the mustard, nutritional yeast, beans and peas.
Stir until everything is well combined and cook for 5 minutes until the cream is bubbling.
Once the pie filling is bubbling, pour into a pie dish and top with the scrunched up filo pastry sheets.
Brush over a little oil (or use an oil spray) and then place into the oven.
Cook for 20 minutes or until the filling is bubbling and the filo is crisp.