Classic Vol-au-Vents. Very impressive and tasty
Place the chicken breasts in the bottom of a 2-quart saucepan. Add the onion halves and cover with chicken stock and wine. Season the liquid with salt and pepper
Turn the heat to high and bring to boiling point. Immediately turn the heat down to low, so that the liquid barely bubbles.
Simmer for 10 minutes, then turn the heat off and let the chicken sit in the hot poaching liquid for 15 more minutes
When cooked, remove from liquid and let sit for 5 to 10 minutes before cutting.
Melt 2 tablespoons of butter in a large skillet.
Add the mushrooms and sautee for 3 to 4 minutes until lightly golden.Add the garlic and thyme and stir well
Add the wine, stirring into mixture. Turn the heat to high and return to simmering point. Decrease the heat and allow simmer for 2 to 3 minutes to reduce the volume of wine by half.
Add the chopped chicken to the mushroom and wine mixture. Turn off the heat and let stand while preparing the cream sauce.
Melt the last 2 tablespoons of butter in another large skillet. Add the flour and stir well to form a roux. Continue to stir and cook over medium heat for 1 minute.
Gradually add the chicken stock, whisking continuously to prevent clumping. Bring to simmer and continue to stir and simmer for 1 to 2 minutes until sauce thickens.
Add the dijon mustard and cream, stirring well to combine.
Add the mushroom, carrots, peas and chicken mixture to the cream sauce. Season to taste with salt and pepper.
Turn the heat up to bring to simmering point again. Reduce heat and stir for 2 minutes. Turn the heat off and let stand for 5 minutes before filling the pastry shells.
Fill the pastry shells with 2 to 3 teaspoons of chicken filling. Place the small pastry lid on top as decoration.
If pastry has cooled, return the filled vol-au-vents to a 375 degree F oven for 5 minutes.
Alternatively, the pastry shells and filling can be made a day in advance.
If so, fill the shells when ready, and heat in a 375 degree F. oven for 15 minutes.