Prepare the cream cheese mixture: In a medium bowl, combine the softened cream cheese, capers, chopped dill, lemon juice, black pepper, and salt. Stir until the mixture is smooth and pale pink from the capers — you’ll see the flecks of green dill and the capers evenly distributed throughout. The smell should be fresh and herby.

Toast the bagels (if desired): Slice each bagel in half and toast them until they are golden brown and firm to the touch, about 2–3 minutes. The surface should feel crisp, not soft, which helps prevent sogginess later. If you’re meal-prepping, toasting is essential for texture.

Spread the cream cheese: Using a butter knife, spread a generous layer of the cream cheese mixture onto the cut side of the bottom half of each bagel. The layer should be about 1/2 centimetre thick — you’ll see it hold its shape without running off the edges. The bagel should feel cool to the touch after spreading.

Layer the smoked salmon: Arrange the smoked salmon trimmings over the cream cheese, distributing them evenly. You’ll see the deep orange-pink fish contrasting with the pale cream cheese. Press the salmon gently so it sticks to the spread.

Add the onions and greens: Scatter the thinly sliced red onion over the salmon, followed by a handful of rocket or watercress if using. The onions should be paper-thin — you’ll hear a slight crunch when you bite into them later.

Close the bagels: Place the top half of each bagel on the fillings and press down lightly. The bagel should feel compact but not squashed — you’ll see the fillings peek out slightly from the sides. Wrap each assembled bagel tightly in parchment paper or cling film.

Store or serve: If eating immediately, serve the bagel as is. For meal prep, place the wrapped bagels in an airtight container and refrigerate for up to three days. The bagel should remain firm to the touch, not soft or soggy, when you unwrap it later.