01 - Preheat the oven to 375°F (190°C) and lightly grease a 6-cup muffin tin.
02 - Combine softened unsalted butter, minced garlic, and chopped parsley in a small bowl.
03 - Flatten each bread slice with a rolling pin. Trim crusts if necessary to fit the muffin cups.
04 - Spread a thin layer of garlic butter on one side of each bread slice, then press bread, butter-side-up, into muffin cups to form nests.
05 - Sprinkle a portion of grated Parmesan cheese into the bottom of each prepared bread cup.
06 - Crack one egg into each bread cup. Season with salt and black pepper. Add shredded cheese if desired.
07 - Bake for 16 to 18 minutes, or until egg whites are set and yolks reach the desired doneness.
08 - Let cool for about 2 minutes. Gently remove each cup with a small spatula.
09 - Serve warm, garnished with extra parsley if preferred.