Special equipment: a 2- to 2 1/2-inch round cutter (the size of the cutter will depend on the width of the baguette), optional
Preheat the oven to 350 degrees F.
Using a 2- to 2 1/2-inch round cutter (the size of the cutter will depend on the width of the baguette), cut out 4 to 6 circular wells down the length of the baguette. The wells should be deep enough to hold an egg; don't cut all the way through to the bottom. The number of wells will depend on the length of your baguette. If you do not have a round cutter, cut out circles with a knife. Scoop out the bread filling and brush the insides of the holes with the butter. If you have any butter leftover, brush the outside of the loaf as well.
Place the baguette on a baking sheet. Crack an egg into a small ramekin and then slide the egg into one of the holes in the baguette. Repeat and fill the remaining holes. Season with salt and pepper.
Bake until the eggs are set and cooked to the desired doneness, about 15 minutes. Garnish with the parsley if using and serve immediately.