If using ready-made pastry take out of freezer or fridge to get to room temperature. Once at room temperature press one sheet into a 9" pie dish. Reserve the other sheet to put on top of the pie once filled.
Preheat oven to 400 degrees.
In large pot or saucepan melt the vegan butter over medium heat and add the flour to melted butter. Combine to form a roux (paste).
To the roux add the vegetable stock, the unsweetened plant-based milk, and the dijon mustard. Whisk together until there are no lumps.
Add the diced potatoes and carrots to the pot, bring to a simmer and cook until fork-tender.
In another pan heat a little olive oil and saute the onion and garlic until soft. To this add the mushrooms, peas, and thyme and cook for about 2 minutes.
Turn the heat off and add the corn, fresh kale and spinach to the pan with the mushrooms and peas. Stir to combine.
Once the potatoes and carrots are tender add the sauteed veggies and the parsley to the sauce mixture. Season with salt and pepper.
Pour this mixture into your prepared pie dish. Cover with the other sheet of pastry and seal the edges.
Bake at 400 degrees for 35-40 minutes or until the pastry is golden brown.
Slice and enjoy