To make the crawfish gravy, melt the butter in a large skillet over medium-high heat. Add the flour to the melted butter, stirring until it is incorporated. Cook for about 3 minutes.
Add the onions, corn, andouille sausage, poblano peppers, celery, salt, black pepper, bay leaf, chipotle powder and Creole seasoning. Cook the mixture, while stirring, until golden brown. Add the milk and tomatoes to the mixture and cook for 15 minutes, while stirring.
Add the crawfish and Worcestershire sauce and simmer for 2 minutes before removing the pan from the heat. If gravy is too thick add more milk. Season to taste and keep warm.
To make the grits, bring the milk to a boil in a small pot. Slowly stir in the grits. Stir continuously and thoroughly until grits are well mixed. Let the pot return to a simmer, cover with a lid, lower the temperature, and cook for approximately 30 minutes, stirring occasionally. Add more liquid if necessary.
The grits are done when they are smooth and creamy. Stir in the butter and the rest of the ingredients until all ingredients have melted and incorporated. Season to taste.
Serve grits in a bowl and top with crawfish gravy.