In a large pot, heat oil over medium heat. Add the onion and sautee until soft and translucent, around 5 minutes.
Add the garlic and rosemary, stirring constantly for one minute.
Add the wine, scraping up all the bits from the bottom of the pan, and cook for 1-2 minutes until volume of wine has reduced to half.
In a large bowl, toss the carrots, celery and sweet potatoes with the flour. Add the mixture to the pot, mixing everything up as best as you can.
Add the chicken stock, bouillon cube, salt and pepper.
Cover and bring to a boil, then remove lid, reduce heat, and simmer for 20 minutes, or until the sweet potato has softened.
*While the sweet potatoes simmer you will want to pre-heat your oven to 375°F.
Stir in the chicken.
At this point, assess whether your sauce is thickened to your preferences. If you wish to have a thicker filling, whisk a tablespoon of flour with a tablespoon of water, then add to the filling. Repeat as needed.
Divide mixture between six 9-ounce ramekins.
Roll out puff pastry to a 10X12 inch square {you will need to get 3 pot pie lids out of one sheet} on a floured surface.
Cut lids to be about a half inch wider than the ramekins. Drape puff pastry over ramekins, brush with beaten egg, and cut a few slits to allow venting while cooking.
Place ramekins on a baking sheet in the oven, and bake for 15-20 minutes, until puff pastry is golden.