In a large stockpot, place the butter and all the vegetables and sauté five minutes until translucent.
Add all the spices and continue to sauté for an additional minute to bloom spices.
Add all-purpose flour to vegetables using a wire whisk.
Cook for an additional five minutes, continuously stirring the mixture so the flour doesn't stick to the bottom of the pot.
Add crushed tomatoes and stock. Continue to stir and simmer until the flour is completely dissolved. The wire whisk helps break the flour up into the sauce.
Season with salt and pepper.
For best results, allow this to cool overnight. Use it the next day to make your crawfish etouffee.
For the Crawfish Etouffee
One day after making the base, bring the etouffee base to a simmer and add two pounds crawfish tail meat along with the fat. Serve over cooked white rice. Garnish with green onions and your favorite hot sauce.