01 - Fill a small saucepan with water and bring to a rolling boil. Gently lower the eggs into the water and boil for 8 to 10 minutes until fully set. Transfer the eggs to a bowl of ice water to cool, then peel and slice into rounds.
02 - While the eggs cook, place the bread slices in a toaster and toast until golden brown and crisp throughout.
03 - Halve the avocado and remove the pit. Scoop the flesh into a small bowl and mash lightly with a fork to your preferred consistency. Season with fresh lemon juice, sea salt, and black pepper, then stir to combine.
04 - Divide the seasoned avocado mash evenly between the two toasted bread slices, spreading it in an even layer across each.
05 - Slice the tomato into thin rounds and arrange them over the avocado layer. Top each toast with the sliced hard-boiled egg halves.
06 - Finish with a sprinkle of chopped chives or parsley and red pepper flakes if desired. Serve immediately while the toast is still warm and crisp.