Heat oven to 400°. Coat an 8 x 8 x 2-inch baking pan with nonstick cooking spray; set aside.
In a small bowl, stir together muffin mix, egg and milk. Pour into prepared baking pan and bake at 400° for 18 to 22 minutes or until lightly browned. Remove to a rack and cool completely.
Cut corn bread into 1-inch cubes and place on a rimmed baking sheet. Bake cubes at 400° for 10 minutes, stirring halfway through or until lightly toasted. Remove from oven and cool completely.
Stir together bacon, tomatoes, scallions, green pepper and pickles. In a small bowl, stir together mayonnaise and pickle juice. In a large serving bowl, place half of the corn bread cubes at the bottom, then top with half of mayonnaise mixture and half of tomato mixture; repeat layers one more time. Chill 1 hour before serving.