Preheat the oven to 400°F.

Place chicken stock in a large soup pot and bring to a boil.

Add diced Yukon Gold potatoes, sweet potatoes, celery root, parsnip, and onion to the boiling stock.

Cover the pot, reduce heat to medium-low, and simmer for 5 minutes.

Add diced chicken breasts to the pot and simmer for 10 minutes, or until chicken is just cooked.

Remove the chicken and vegetables from the stock with a slotted spoon and reserve.

In a mixing bowl, place the flour.

Gradually add milk to the flour, whisking until well blended.

Add the milk mixture to the stock and bring to a simmer for 5 minutes or until thickened.

Add peas, parsley, cilantro, hot sauce, reserved chicken, and vegetables to the stock.

Season with salt and pepper.

Place four 16-ounce ramekins on a baking sheet.

Fill the ramekins with the chicken and vegetable mixture.

Cut the puff pastry into 4 pieces.

Lay each piece of puff pastry over a ramekin.

Gently press the dough over the edges of the ramekins.

Bake for 20 to 25 minutes, or until the puff pastry is golden brown and the filling is bubbly.

Place the hot ramekins on serving plates and enjoy.