Steps
1. Preheat the oven to 400°F (200°C).
2. Peel and dice the potato into small cubes. Toss with olive oil, salt, and pepper.
3. Spread the potatoes on a baking sheet and roast for 20 minutes or until golden and crispy.
4. While potatoes roast, hard boil the egg: place egg in boiling water for 9 minutes, then cool and peel.
5. Mash the boiled egg with mayonnaise, salt, and pepper to make the egg mayo spread.
6. Toast the bread slice until golden brown.
7. Spread the egg mayo evenly on the toasted bread.
8. Top with roasted potatoes and thin slices of fresh tomato.
9. Garnish with fresh herbs if desired and serve immediately.