To make spicy aioli, mix mayonnaise, lemon juice, hot sauce and garlic in a small bowl. Set aside. Butter one side of each of the four bread slices. Melt remaining butter in a small skillet over medium high heat and add the Trinity (bell pepper, celery and onion) and saute until softened but not browned - about 4 minutes. Add crawfish meat, Creole seasoning and grated Havarti. Toss well to combine all ingredients and heat about 1 minutes. Remove from heat and allow cheese to begin melting in hot skillet. In a large skillet or on a griddle set to medium high heat, place two slices of bread, buttered side down. Top each bread slice with half of the cheddar cheese, evenly spread. Grill for about 3 minutes or until bread is brown and crisp and cheddar begins to melt. Top cheddar on each sandwich with half of the crawfish mixture and then half of the green tomato relish. Spread spicy aioli on unbuttered side of remaining two bread slices. Place aioli side down on the sandwich filling. Using a large spatula, turn sandwich to grill the top slice of bread. Press down slightly to meld ingredients. Grill for about 3 minutes or until bread is crisp and brown. Serve immediately with a large glass of sweetened iced tea. *If you cannot find green tomato relish, use bread and butter pickles. Makes two sandwiches.