Cut the top off the sweet peppers. Removes the seeds and cores from the peppers and discard. Set the peppers with the tops aside for later.
To make the jambalaya, sauté 1/4 cup butter, onion, celery, jalapeno, and garlic in a large skillet on medium heat. After sautéing a few minutes, stir in the Cajun seasoning, cayenne pepper, crawfish tails, tomato paste, rice and water. Bring to a boil, lower heat, cover and cook for 12 minutes.
Stuff the sweet peppers with the crawfish jambalaya until starting to overflow and place the top of the pepper back on. Bake in a 350F oven for 30 minutes.
While the peppers are in the oven, make the country gravy. Melt the 1/3 cup butter in a saucepan on medium low heat. Whisk in the flour to make a roux. Continue to stir for a few minutes allowing the colour of the roux to turn a very light brown. Stir in the milk until it is a smooth even consistency. Add the black pepper. Cook for a few more minutes to allow the gravy to thicken.
Serve the stuffed peppers on a plate with gravy ladled around it. If you have some extra cooked crawfish tails, toss a few on the gravy around the pepper