Preheat oven to 400 degrees. Heat 1 tablespoon oil in a saute pan, add finely-diced vegetables and cook 1 minute until tender. Add garlic and 6 ounces of crawfish tails; cook, tossing, 3 minutes. Remove from heat and stir in bread crumbs; adjust seasonings to taste with Creole spice.
Using a small knife, cut a 1 1/2- to 2-inch pocket in side of each fillet. Move your knife around inside fillet to make room for stuffing. Divide stuffing and fill up each fillet; season outside of steak with Creole spice. Heat remaining oil in a saute pan, add stuffed steaks and sear well on all sides until browned. Transfer to a baking dish and roast 8 to 10 minutes for medium-rare steaks. To saute pan add shallots and cook in pan drippings, tossing for 1 minute. Add stock, scraping up browned bits to incorporate them in sauce, bring to a boil, lower heat and slowly reduce liquid by half. To finish, stir in remaining 2 ounces crawfish tails, butter and green onions and simmer until heated through. Serve steaks with sauce poured over.
Yield: 2 servings