Spread mayonnaise evenly on cut side of bread. Set aside.
In a large skillet, melt butter over medium heat. Cook onions until softened (4-5 minutes). Add chopped garlic and continue to cook for another 2-3 minutes. Add crawfish tails, green onions, and parsley, stirring to combine. Cook until crawfish is heated through.
Add Freelance Spice Rub
Add cream cheese, remove from heat. Stir until cream cheese is incorporated, and melted.
In a small bowl, combine Parmesan and Pepper Jack Cheeses.
Place bread on baking sheet
Divide Crawfish Mixture evenly onto bread halves. Spread evenly to cover. Top each with cheese mixture. Sprinkle with more Freelance Spice Rub if desired.
Bake until cheese is melted (12-14 minutes)
Increase temperature to broil. Broil until cheese has browned. Top with more parsley as garnish.
Allow to cool slightly then slice, and serve warm.