In a small bowl whisk together the mayonnaise, chili powder, smoked paprika and Worcestershire sauce. Cover and place in the icebox for 30 minutes, or until ready to serve.
Lay the bacon in a single layer on a baking sheet. Generously coat both sides with pepper. Cover and set in the icebox for 30 minutes.
Remove from the icebox and place in a skillet and fry over medium-high heat until done, but not too crispy. *Note you can also bake the bacon at 400 degrees F. for about 10 minutes or until done. Remove to a paper towel.
Meanwhile, sprinkle each side of the tomato slices with brown sugar. Cover and set aside.
Spread butter on both sides of the bread. Place in a cast iron skillet and toast both sides until golden brown.
To assemble the sandwich: Spread a layer of the mayonnaise sauce on top of the bread, add a layer of avocado, 4 pieces of bacon, avocado, butter lettuce and 2 slices of tomato. Top with bread. Repeat with the remaining ingredients. Serve immediately.