I start by toasting the sourdough until it's golden and firm enough to hold weight. A lighter toast works fine too, but I find a deeper golden color gives the base more crunch against the creamy avocado. This step takes almost no effort, so I let it run in the background while I prep everything else.
While the bread toasts, I scoop the avocado into a small bowl and mash it with a fork, leaving a few small chunks for texture. I stir in the lemon juice right away so it doesn't turn brown, then season with salt and pepper. I taste it here because this is really the flavor base for the whole toast.
I heat the olive oil in a nonstick skillet over medium-low heat, then crack in the eggs gently so the yolks stay intact. I cover the pan for a minute or two so the whites set fully while the yolk stays soft. If you prefer a firmer yolk, just leave it a little longer.
Once the toast is ready, I spread the mashed avocado generously over each slice, right to the edges. I slide the egg on top, season it with a touch more salt and pepper, and add red pepper flakes or herbs if I'm using them. I serve it immediately while the egg is still warm.