Prepare the quick-pickled fennel: Put the thinly sliced fennel in a small bowl and toss with 1 tsp white wine vinegar and a pinch of sea salt. Let it sit while you prepare the rest (about 5–10 minutes). Why: the vinegar softens the fennel's raw bite and brings a lively acidity that contrasts the salmon and avocado; a short quick-pickle brightens flavor without making the fennel soggy.

Warm and toast the bread: Heat a heavy skillet over medium-high heat (or preheat a grill pan). Toast the sourdough slices 1–2 minutes per side until golden and just crisp at the edges. Alternatively, use a toaster and finish in a warm dry skillet to get a specially caramelized surface. Why: toasting creates a sturdy, crunchy base that holds the wet toppings and develops Maillard flavors that deepen the overall taste profile.

Season the avocado: In a small bowl, mash the 1/2 avocado with a pinch of sea salt, 1/2 tsp lemon juice, and a light crack of black pepper. Taste and adjust—the lemon keeps the avocado bright and prevents quick discoloration. Why: simple seasoning lets the avocado’s buttery texture shine and lemon balances the richness, while salt enhances overall flavor.

Build the base layer: Spread an even layer of the mashed avocado onto each warm toast while the bread is still hot. Why: applying avocado to warm toast slightly softens it so it melds into the bread surface, creating a cohesive bite rather than a loose topping that slides off.

Arrange the smoked salmon: Fold or loosely roll the smoked salmon slices and tuck them over the avocado on each slice (about 30 g salmon per slice). Why: folding creates height and delicate layers so each bite has a mix of salmon and avocado; it also looks elegant and restaurant-polished.

Top with pickled fennel and dill: Scatter the quick-pickled fennel evenly across the two toasts, then sprinkle the chopped fresh dill and the lemon zest. Why: the crunchy, acidic fennel cuts through the richness; dill and lemon zest add aromatic brightness that ties the dish together.

Finish and season: Drizzle each toast with 1/2 tsp extra-virgin olive oil (total 1 tsp for both), a small pinch of sea salt, and a final crack of black pepper. Serve immediately. Why: the olive oil adds a silky mouthfeel and flavor richness; finishing salt and pepper make the flavors pop—add them at the end so they remain pronounced.

Plating suggestion: Place the toasts on a warm plate, garnish with an extra sprig of dill and a very light grating of lemon zest for aroma. Serve with a wedge of lemon on the side if you like extra brightness. Why: warm plating keeps textures optimal; an aromatic finishing zest awakens the nose as you eat.