Step 1

Preheat the oven to 350 degrees F (175 degrees C). Grease a 12 cup muffin pan with cooking spray.

Step 2

In a large skillet, fry the bacon pieces over medium heat until browned and crisp, about 8 minutes. Drain off half of the grease. Transfer the bacon and remaining grease to a large bowl. Stir in the shredded potato, shallot and Parmesan cheese. Divide this mixture evenly between the muffin cups. Pour eggs into each cup, filling to the top.

Step 3

Bake in the preheated oven until the egg is firm, about 12 minutes. Remove from the oven and set the dial to Broil. Place a slice of tomato onto each cupcake and return to the oven. Broil for about 3 minutes, or until toasted. Allow to cool slightly, then arrange the cupcakes on a tray and top each one with a slice avocado, if using.