01 - Place eggs in a saucepan and cover with cold water. Bring to a rolling boil over high heat, then cover the pan, remove from heat, and let stand for 9 to 10 minutes. Transfer eggs to a bowl of ice water to cool completely, then peel and slice into rounds.
02 - Toast the bread slices in a toaster or on a skillet over medium heat until golden brown and crisp on both sides.
03 - While the bread is toasting, halve the avocado and remove the pit. Scoop the flesh into a mixing bowl and add the lemon juice, salt, and black pepper. Mash with a fork until the mixture is creamy but still retains some texture.
04 - Divide the mashed avocado evenly and spread it across both toasted bread slices, pressing gently to adhere. Layer tomato slices over the avocado, then arrange the sliced hard-boiled eggs on top.
05 - Drizzle with olive oil if desired. Season with additional salt, pepper, fresh herbs, and a pinch of crushed red pepper flakes. Serve immediately while the bread is still warm and crisp.