1. Thaw the lobster tails in the refrigerator overnight or in cold water for 30 minutes.

2. Steam or boil the lobster tails until shells turn red and meat is opaque, 6-8 minutes.

3. Cool slightly, remove the meat from the shells and chop into bite-size pieces.

4. Preheat the oven to 400°F (200°C).

5. In a saucepan, melt butter over medium heat and sauté onion, carrots, and celery until softened, about 5 minutes.

6. Add minced garlic and cook for 1 minute.

7. Sprinkle flour over the vegetables and stir to form a roux.

8. Gradually whisk in seafood or chicken stock and heavy cream until the sauce is smooth and thickened.

9. Season the sauce with thyme, salt, and pepper.

10. Fold in the chopped lobster meat and optional peas or corn; heat through for 1-2 minutes.

11. Pour the filling into an 8×8 or 9×9 inch baking dish.

12. Drape the puff pastry or pie crust over the filling, trim excess, and crimp edges to seal.

13. Brush the crust with egg wash for a golden finish.

14. Bake for 25-30 minutes until the crust is deep golden and the filling bubbles.

15. Let the pot pie rest for 10 minutes before serving.