Remove pits from avocados by cutting them in half lengthwise. Using a spoon, carefully remove a small amount of the avocado flesh around the pit to give the egg more space.
Into a small bowl, crack one egg. Transfer this carefully to one of the avocado halves. Place the avocado on the muffin tin and repeat the process for all four halves. Season each half with salt and pepper to taste.
Place into pre-heated oven and bake for 20-25 minutes (or until eggs are cooked to your desired consistency).
Remove baked avocados from oven. Top with cheese and bacon. If desired, garnish with sliced green onions or chives. Serve immediately.