Interesting topic. From what I can tell (and I'm no expert!) it looks like New Orleans turtle soup is different from the northern versions; and I wonder if Cajun turtle sauce piquante or soup are yet another theme, so to speak. Heree's a recipe for the former:
5 lb Turtle meat, cut 2" cubes
3 pt Water, cold
32 oz Tomatoes, whole, can
1 t Garlic, finely chopped
6 oz Tomato sauce
1/2 c Celery, finely chopped
12 oz Mushrooms + liquid
1/2 c Shallots, finely chopped
4 ea Onions, white, finely chop
1/3 c Bell pepper, finely chopped
1/4 c Parsley, finely chopped
3 ea Lemon peel, small slivers
1 x Cayenne pepper/generous
1 x Salt & pepper to taste
Fry meat in minimum oil til tender to fork. Usually 20 - 35 minutes. Remove.
Make a roux of 6 Tbsp oil to equal amount flour. When deep (not dark) brown, add onion. Cook until transparent but don't burn.
Add 3 pints cold water and bring to a boil. Add tomatoes, tomato sauce, celery, bell pepper, shallots, garlic, mushrooms. Let boil about 15 or 16 minutes. Add fried turtle meat, parsley, lemon peel and salt & pepper to taste. Let simmer over low fire for at least one hour. Serve over hot rice.
Also for: Any tough meat, such as large alligator, raccoon.