Cook the bacon. (I cooked an entire package in the oven. Saved some for next day's breakfast.)
Remove the leafy outside and slice the tomatillos. Add the olive oil to a skillet and saute the tomatillos over medium-high heat for about 3 minutes, or until begin to turn opaque. Flip and saute another minute or two, remove from heat. Season with salt and pepper.
Pull apart the lettuce and fold into sandwich size pieces.
Spread mayo on both pieces of bread (or one side if you want less mayo), assemble sandwich with lettuce, 2 slices of bacon, broken to fit, and sauteed tomatillo slices.
Serve B-L-Tomatillo Sandwich with sides.