Choose and prep the avocado: halve the ripe Hass avocado, remove the pit, and scoop the flesh into a bowl. Mash with a fork until mostly smooth but with a few small chunks — this gives a creamy texture with pleasant bite. Mix in the lemon juice (to brighten flavor and slow browning), 1/4 teaspoon flaky sea salt, and a pinch of black pepper. Taste and adjust seasoning; the acidity and salt make the avocado pop against the bread.

Toast the bread for maximum crunch: spread the 1 teaspoon of butter thinly on both sides of each slice (butter browns and adds nutty flavor). Toast the slices in a preheated skillet over medium-high heat (or in a toaster) until golden and crisp, about 1–2 minutes per side in the skillet. Press lightly with a spatula to ensure full contact — the goal is a sturdy, golden base that contrasts with the creamy avocado and won’t go soggy.

Warm the pan and prepare for the eggs: wipe the skillet clean, lower heat to medium, and add 1 teaspoon of the olive oil. Give it 20–30 seconds to shimmer — heating oil before the egg helps prevent sticking and promotes even browning. If you prefer a poached egg (recipe includes poaching alternative below), ready a pot of simmering water with 1 tablespoon vinegar now.

Cook the eggs (two methods): - Fried (recommended for beginners): crack each egg into the warm skillet. Cook gently over medium heat until whites are set but yolks still runny, about 2–3 minutes for sunny-side-up. For a slightly set top, cover the skillet for 20–30 seconds — the steam finishes the white without overcooking the yolk. Season with a pinch of salt and pepper while cooking. - Poached (restaurant-style, slightly more advanced): bring a saucepan of water to a gentle simmer, swirl with a spoon to create a vortex, and slip each cracked egg into the center. Cook 3 minutes for a soft runny yolk. Remove with a slotted spoon and drain on paper towels. Vinegar helps the white coagulate quickly and keep shape.

Build the toast: while the eggs cook, divide the avocado mash between the two toasted slices, spreading evenly to the edges to create a generous layer. The lemon oil-avocado emulsion helps the spread adhere to the bread and adds brightness.

Top and finish: gently place one cooked egg on each avocado-covered slice. Drizzle the remaining 2/3 tablespoon of olive oil over the toasts (olive oil brings fruitiness and a silky finish). Sprinkle the remaining 1/4 teaspoon flaky sea salt, a crack of fresh black pepper, and a pinch of red pepper flakes for heat. Garnish with chopped chives or cilantro for freshness and color.

Serve immediately: serve each toast right away while the bread is still warm and the egg yolk is runny — the molten yolk will mingle with avocado and soak slightly into the toast for the ideal texture contrast. If not serving right away, keep eggs warm in a 200°F (95°C) oven for up to 5 minutes; avoid long holding, which will firm yolks.