Set the Instant Pot to the saute function, add the oil and when it heats up, add the shallots or leeks, celery, carrots and garlic with some salt and ground black pepper. Saute, stirring frequently, a couple of minutes until the onions begin to soften.
Add the rosemary and potatoes with the vegan sausage, making sure you crumble the sausage into little bits or run it once through the food processor before adding. Mix well, and add the beans and 3 cups of vegetable stock.
Cover the Instant Pot and set it to the "chili" function, which is 30 minutes of pressure cooking time. At the end of cooking, you can either wait for the pressure to release, or release it manually after 10 minutes.
Place the cashews in a blender with the remaining 1/2 cup of vegetable stock. Blitz into a smooth cream.
Put the IP back at the saute function, add the cashew cream, and let it warm through. Check at this time if you need more ground black pepper.
The filling should be pretty thick, but if you want to thin it out, add more stock.
Make the puff pastry topping by first preheating your oven to 375 degrees. Unroll the puff pastry sheet and cut it into pretty shapes using a cookie cutter. You can make one large disc that will sit on top of your ramekin, or smaller shapes, like the hearts I made.
Place the puff pastry shapes on a baking sheet and bake in the preheated oven 15 minutes or until golden and puffy.
Ladle the pot pie filling into ramekins, top with the puff pastry, and serve piping hot.