Preheat oven to 190˚C/375˚F/Gas Mark 5.
Roll out the pastry block to fit a large flan dish (diameter about 25-28 cm/10-11 inch). Spread around evenly with your thumb and fingers.
Roll a rolling pin over the top of the pastry case to remove the excess pastry.
Refrigerate while you prepare the filling.
Heat some oil in a large frying pan with a lid, on a low-medium heat, and add the leeks. Pop the lid on and leave for 5 minutes.
Remove lid, add the mushrooms and turn up the heat.
Stir frequently for a few minutes.
Add the garlic, fresh or dried parsley and add salt and pepper, to taste. Cook for a further couple of minutes and turn off the heat.
In a high speed blender add the tofu, cream cheese, plant milk, nutritional yeast, turmeric, lemon juice, vegan syrup, Dijon mustard, corn flour, salt and pepper and blend until very smooth. Taste the mixture and add more salt, syrup, turmeric, nutritional yeast if desired.
Remove the pastry case from the fridge and spoon a bit of the leek/mushroom mixture into the bottom. Crumble half of the blue cheese over the base. Add half of the tofu mix and until evenly spread. Repeat this stage again until all of the vegetables, tofu mix and cheese have been used up. Make sure you crumble some of the cheese and layer some of the veg on the top of the quiche.
Cover the top of the quiche with foil or baking parchment and bake for 20 minutes. Remove the foil/baking parchment and bake for another 15-20 minutes or until golden and the cheese is bubbling. Enjoy.