1. After removing pastry shells from oven, take the tip of a thin, sharp knife, and carefully cut out the tops from each pastry and discard the moist insides. Cool pastry shells.
2. Heat the olive oil in a large skillet over medium-high heat.
3. Add the mushrooms, salt and pepper.
4. Cook, stirring occasionally, until the mushrooms soften, about 4 minutes.
5. Add the shrimp, green onions, shallots, and garlic and stir-fry for 1 minute.
6. Remove the pan from the heat and add the Cognac.
7. Have a large lid nearby.
8. Return to the heat, and very carefully ignite the brandy.
9. Once the flame goes out(you may need to cover with the lid to extinguish, if the flames leap too dramatically,)add the cream, mustard, and parsley; stir well.
10. Reduce the heat to medium-low and simmer for 2 minutes.
11. To serve, place a pastry shell on each of 6 plates.
12. Spoon the shrimp mixture into each shell.
13. Serve immediately with a nice bottle of Chardonnay.