Cut avocado in half and carefully remove the pit. Slice off a small slice of the bottom of each half (just enough that they sit still without rolling around) and place them on a rimmed baking sheet lined with foil.
Separate the egg whites from the yolks, being careful not to break the yolks. Slip an egg yolk into the hole in each avocado half. (If the hole doesn’t look big enough, scoop out a little avocado to make more room.
Carefully pour in enough egg white to fill up the rest of the whole. A little overflow is okay!
Bake for 15 minutes.
While the avocados are baking, cook the bacon until crispy and drain on paper towels.
Place baked avocados on a plate, scatter with bacon and scallions and serve, either just as they are or with warm toast.