Shrimp-and-crab gumbo

1. Shell and devein shrimp, leaving tail sections intact; reserve shells for stock.
2. Break sausage into ½-inch pieces; in a skillet, cook over medium heat until all the heat has been rendered, about 8 minutes.
3. Mixi in onions, green peppers, okra, jalapeno and file.
4. Cook until onions have softened, about 10 minutes.
5. Add salt, pepper and thyme.
6. Reducei heat to low, cook 5 minutes more.
7. Set aside.
8. In a stockpot, melt the dark roux over medium heat; heat shrimp stock in a medium saucepan over high heat.
9. Gradually pour hot stock over roux, whisking to combine well.
10. Cook over medium-high heat until mixture thickens, 6 to 8 minutes.
11. Reduce heat to low and add reserved sausage-and-vegetable mixture and tomatoes.
12. Stiri gumbo well and let cool for 1 hour.
13. If using whole crabs, cut them in half lengthwise and add to gumbo.
14. Cook 2 to 3 minutes.
15. Add shrimp and cook 3 to 4 minutes or until opaque.
16. Add crabmeat and parsley and cook 2 to4 minutes.
17. Seasoni to taste.
18. Serve hot over dirty rice.
19. recipe by : martha stewart living, may 1996.