Return the skillet to the heat, then add the remaining tablespoon olive oil. Once the oil is hot, add the bacon pieces and cook, stirring occasionally, until golden brown and crisp, 7-10 minutes. With a slotted spoon, transfer the pieces to a paper towel-lined plate.
Heat 1 tablespoon olive oil in a large, deep skillet over medium. Saute the mushrooms until browned and they have given up their juices, about 8 minutes. Remove from the pan and set aside.
Preheat your oven to 350 degrees F. Spread the bread cubes in an even layer on an ungreased baking sheet. Bake until the cubes are lightly toasted, about 12 minutes, stirring twice during the baking to ensure they toast evenly. Let the cubes cool, then place them a very large mixing bowl. Increase the oven's temperature to 375 degrees F. Lightly coat a 9x13-inch dish with baking spray and set aside.