Start by melting a little butter in a frying pan over medium-low heat. Toast the sourdough slices for 1-2 minutes on each side until they turn golden brown and crispy.
Take the sourdough toast out of the pan and place on a cutting board or plate. Spread a layer of mayo on one side of both sourdough slices. Set them aside.
Add bed of arugula on one slice. Fry slices of bacon until crispy and place it over arugula.
Fry an egg on medium-high heat. Once egg is almost cooked to desired amount, place cheese slice on top. Cook for a few more seconds and place it over the bacon.
Layer fresh avocado slices on top of the egg. Finish with sea salt and a few grinds of black pepper. Add second slice of sourdough over the avocado. Cut sandwich in half. Enjoy