Preheat a skillet over medium heat. Butter both sides of the sourdough slices lightly (about 1/2 tbs butter per side) and toast in the skillet until golden brown and crisp, 2–3 minutes per side. Transfer to a warm plate and keep warm.

In the same skillet, add 1 tbs olive oil and warm over medium. Add baby spinach and sprinkle with dried seaweed flakes, 1/2 tsp salt and 1/4 tsp black pepper. Sauté just until wilted, about 1–2 minutes. Remove from heat and keep warm.

For the crab roe hollandaise

Clarify/melt butter

Gently melt 120 g butter in a small saucepan over low heat until fully liquid. If you prefer a clearer sauce, skim foam and pour off clear butter, leaving milk solids behind. Keep butter warm but not hot.

Prepare double boiler

Set a heatproof bowl over a saucepan of barely simmering water (water should not touch the bowl bottom). Ensure the bowl is stable and the steam is gentle.

Whisk 3 egg yolks, 1.5 tbs lemon juice, Dijon mustard and 1 tsp cold water together in the bowl. Whisk continuously over the gentle heat until mixture thickens slightly and becomes pale and ribbon-like (2–4 minutes). Be careful not to scramble.

Very slowly drizzle the warm melted butter into the yolk mixture while whisking constantly, starting drop by drop and increasing to a thin stream as the emulsion forms. Continue until all butter is incorporated and the sauce is thick and glossy.

Remove the bowl from heat. Stir in the crab roe (30 g) until evenly distributed. Season with 1/2 tsp salt and 1/4 tsp white pepper. If the sauce is too thick, whisk in up to 1 tsp warm water or lemon juice to reach a pourable consistency. Keep the hollandaise warm (place bowl over warm but not hot water) until plating.

For the poached eggs

Bring 2 L water to a gentle simmer with 1/2 tsp salt and 2 tsp white vinegar in a wide saucepan. Create a gentle whirlpool with a spoon to help eggs hold shape.

Crack each egg into a small cup or ramekin. Lower the cup close to the surface and slip the egg gently into the center of the whirlpool. Poach 3–3½ minutes for runny yolks. Poach in batches if needed (work in two rounds of two eggs).

Use a slotted spoon to lift each egg, gently blot with a kitchen towel or paper towel to remove excess water. Keep eggs warm on a plate in a low oven (about 80–90°C / 175–195°F) while finishing remaining eggs and plating.

For assembly and garnish

Place one toasted sourdough slice on each serving plate. Divide the sautéed spinach evenly and arrange on top of each toast to create a bed.

Tuck 30 g of smoked salmon (about 30 g per toast) over the spinach on each slice in a loose fold.

Carefully place one warm poached egg on top of the salmon on each toast.

Ladle 2–3 tbs of the crab roe hollandaise over each poached egg so it cascades over the egg and salmon. Use more or less to taste.

Finish with a sprinkle of furikake (about 1/4 tsp per serving) and a small spoonful (about 1/2 tbs) of ebiko atop the hollandaise for crunch and color.

Drizzle about 1/2 tbs green oil around the plate and a small dot atop each egg for visual contrast. Scatter microgreens or a sprig of dill if using, and serve with a lemon wedge on the side.

Serve immediately so eggs remain runny and hollandaise is warm. Provide extra lemon if desired.