Bring a large pot of water to a boil. Add the sweet potato, butternut squash and parsnip cubes and simmer until just tender — about 10-15 minutes. Drain and set veggies aside.

In another large pot, heat the olive oil over medium heat. Add the onion and leek and saute for about 5 minutes until tender. Then, add the carrots and mushrooms and continue to saute for another 10 minutes until carrots are tender. Sprinkle with the flour and mix until combined.

Add the vegetable stock/broth and cream and raise the heat to high. Add salt, pepper and oregano and bring mixture to a boil, stirring continuously until very thick.

Add cooked root veggies to the pot and season additionally to taste.

Preheat oven to 425F.

Roll out puff pastry on a floured surface and slice into four large squares (if making individual pies). If making just one pie, leave the puff pastry in one large rectangle.

Divide filling amongst four miniature oven-safe cocettes or a 9 x 13 inch casserole dish. Drape pastry over the tops of the cocettes (or over the top of the dish) and brush with beaten egg.

Bake pot pies for 10 minutes then lightly cover with tin foil and bake for an additional 20 minutes, until pastry is deep golden brown and puffy. Serve immediately.