01 - Fill a small saucepan with water and bring to a rolling boil. Gently lower the eggs into the water and cook for 8 to 10 minutes until hard-boiled. 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 on the outside.
03 - Halve the avocado and remove the pit. Scoop the flesh into a small bowl and mash lightly with a fork. Season with fresh lemon juice, sea salt, and black pepper to taste.
04 - Divide the mashed avocado evenly and spread it across both toasted bread slices, pressing gently to adhere.
05 - Slice the tomato thinly and layer the slices over the avocado spread on each toast.
06 - Arrange the sliced hard-boiled egg over the tomato on each toast. Finish with chopped chives or parsley and a sprinkle of red pepper flakes if desired. Serve immediately.