Prep ingredients: thinly slice the cucumber and tomato. Roughly mash the avocado in a small bowl and season with salt and pepper.

Heat a skillet over medium heat. Butter one side of both bread slices and place butter-side down in the skillet. Cook 3-4 minutes until deeply golden and crispy. Set aside on a wire rack.

In the same skillet, add a drop of oil and briefly blister the thick tomato slices for 1-2 minutes per side. Season lightly and remove from pan.

Lower heat to medium-low. Add remaining olive oil and crack the egg into the skillet. Cook until the whites are set but the yolk remains runny (about 3 minutes). Season with salt, pepper, and fresh herbs.

Assemble: Spread mashed avocado on the un-toasted side of the bottom bread slice. Layer with cucumber slices, then the blistered tomatoes.

Carefully place the fried egg on top of the tomatoes, then crown with the top slice of toasted bread (crispy side up). Serve immediately.