Brush one side of each slice of bread with olive oil. Place 1 slice of mozzarella and 1 slice of cheddar on each side of what will be the inside of the sandwich, layer that with 2 pieces of bacon.
Using an ice cream scoop, place a scoop of egg salad in the middle of 2 of the slices of bread. Do not spread the egg salad. It will spread when you put it in the panini maker. Place top bread over each sandwich and place in a panini maker on medium high heat. Cook until cheese begins to melt. Try not to let any of the egg fall out of the sandwich, you just want to toast the bread and melt the cheese. This is where I stop. It's simple and boy is it tasty. However, with one's imagination, one could add many things like onions, lettuce, black or green olives, chopped celery or who knows what.