Place eggs with 1 cup (250 ml) water in a small saucepan and bring to a gentle simmer over a medium heat. Cover with a lid and simmer for 5-8 minutes, depending on how hard or soft you prefer the yolk to be. Cook for 5-7 minutes for soft yolks and 8-10 minutes for firm yolks.
Place eggs in egg cups and serve with slices of avocado and tomato. Lightly season avocado, tomato and egg with the salt and pepper. Add a squeeze of lemon juice to the avocado, if preferred.
Cut toast into thick strips to dunk into the egg or to spread with avocado.