Pop your two slices of bread into the toaster and let them go until golden and crisp on the outside. I like whole grain bread because it adds a nutty flavor and extra fiber, but any sturdy bread works well here. A good crunch matters since it holds up better once the avocado goes on top.
While the bread toasts, scoop the avocado flesh into a small bowl and mash it with a fork until it reaches your preferred texture. I like mine slightly chunky rather than completely smooth, since it gives the toast more character. Add the cilantro, lime juice, salt, and pepper, then stir everything together.
Once the bread pops up golden and warm, spread half of the avocado mixture generously over each slice. I like to spread all the way to the edges so every bite gets that creamy, tangy flavor. Sprinkle red pepper flakes on top if you want a little extra heat.
If you're making this for breakfast, cook an egg however you like it best. I usually go for sunny side up because I love watching that yolk break over the avocado. Poached, scrambled, or hard-boiled eggs work just as well if that's more your style.
Avocado toast is best enjoyed the moment it's made, while the bread is still warm and crisp. Give it one more light sprinkle of salt and pepper right before serving. Slice it in half diagonally if you want it to look extra appetizing on the plate.