In a seasoned cast iron skillet, fry the bacon over medium-low heat. When bacon is cooked to desired crispness, remove and drain on a paper towel.
Heat a separate skillet over medium heat. Add two pats of butter, place a slice of sandwich bread over the butter, and move it around in the pan to evenly absorb the melted butter. Fry the bread in the butter until lightly toasted, then flip over and lightly toast the other side. Once toasted, remove to a place with the buttered side facing up, and let cool.
Slice the garden tomato into ¼ inch thick slabs. Sprinkle one side with salt and pepper.
Slather mayonnaise onto the buttered sides of the toasted bread.
Lay lettuce across the bottom slice - this acts as a barrier for the juicy tomato, so it doesn't make the toasted bread soggy. Next place a tomato slice on top of the lettuce. Cut the two bacon slices in half, then place them on top of the tomato in a 2x2 pattern.
Optionally top with avocado slices (this would make it into a B.L.A.T.).
Top with the remaining slice of toast, then cut the sandwich in half on a bias, plate and serve.