Cut the chicken breast into thin strips. Sauté them in a small amount of olive oil until lightly golden. Remove the chicken with a slotted spoon and set aside. In the same pan, cook the finely chopped shallot, then add the mushrooms cut into small pieces.

Cook until the mushrooms release all their liquid. Return the chicken to the pan, pour in the white wine, season with salt and pepper, and let simmer for about 20 minutes. Stir in the cream.

Continue cooking for 5 more minutes to let the sauce thicken and take on some color. Warm the puff pastry shells in a low oven, then fill each with a spoonful of the filling (without sauce) to keep the pastry crisp. Serve the remaining filling and sauce separately in a serving dish.