Preheat your oven. Set it to 400°F (200°C). Lightly oil a small baking dish so the avocados don’t stick.
Prep the avocados. Slice each avocado in half lengthwise and remove the pits.
Scoop out a bit of flesh from each half to make a larger well—about 1–2 tablespoons per half. Save the extra avocado for topping or another use.
Stabilize the halves. Nestle the avocado halves in the baking dish so they sit level. You can also crumple a ring of foil under each half to keep them from tipping.
Brush and season. Brush the cut surfaces with olive oil or butter.
Season the wells with a pinch of salt and pepper for flavor from the inside out.
Crack the eggs. Crack one egg into a small bowl first. Gently pour the yolk and as much white as will fit into the avocado well. If there’s extra white, discard it or save for another recipe.
Repeat with the remaining eggs.
Bake. Place the dish on the middle rack. Bake 12–15 minutes for runny yolks, 15–18 minutes for jammy, and up to 20 minutes for fully set. Check early—the difference between jammy and firm happens fast.
Add toppings. In the last 2–3 minutes, sprinkle on cheese so it melts nicely.
Bacon, herbs, or seasoning can go on after baking for texture and brightness.
Finish and serve. Let cool 2 minutes. Add a final pinch of salt, pepper, and a squeeze of lemon or dash of hot sauce if you like. Serve warm.