- Preheat oven to 180°C (350°F).
- Heat butter in a small saucepan over medium-high heat. Add flour. Combineusing a whisk and cook, stirring, 1 or 2 minutes. Add beef broth and bring to a boil while whisking. Add the diluted cornstarch and simmer 5 minutes, stirring regularly, until sauce thickens. Set aside.
- Heat oil in a skillet, over medium-high heat. Add shallots, carrot, and parsnip. Sauté for 5 minutes. Add oyster mushrooms and continue sautéing for 5 minutes.
- Add sauce to vegetables and scrape the bottom of the skillet to remove browned bits. Add pieces of duck. Reduce heat to medium-low and simmer uncovered for about 5 minutes or until duck is heated through. Adjust seasoning as needed. In the meantime, place puff pastry shells in oven and bake for 5 minutes or until hot.
- Spoon duck sauce into puff pastry shells and garnish with fresh parsley. Serve with a mixed green salad.
To prepare a more festive sauce, add a bit of red wine! After sautéing the vegetables, remove from skillet and deglaze with 60 mL (1/4 cup) red wine. Reduce by half. Return vegetables to pan, add reserved sauce and duck, and reheat.