Prepare the shrimp: Place the raw shrimp on a clean cutting board and cut them into roughly 1cm pieces. You'll notice the flesh is firm and slightly translucent, with a faint, sweet scent of the sea.

Marinate the shrimp: In a medium, non-reactive bowl (glass or ceramic is perfect), combine the diced shrimp with the fresh lime and lemon juice. Stir gently to ensure every piece is submerged in the citrus. The shrimp will begin to change colour almost immediately, turning from translucent grey to a delicate, opaque pink at the edges.

Chill and 'cook': Cover the bowl tightly with cling film and place it in the refrigerator for 20-25 minutes. After about 10 minutes, give it a gentle stir. The shrimp should be fully opaque, firm to the touch, and no longer translucent in the centre. The texture will be tender, not rubbery.

Prepare the vegetables: While the shrimp marinates, prepare your vegetables. Finely dice the red onion, tomatoes, cucumber, and jalapeño. The onion should have a sharp, pungent aroma that will mellow as it sits. The tomatoes should be vibrant red and juicy.

Drain the shrimp: Once the shrimp is 'cooked' by the citrus, pour the mixture into a fine-mesh sieve set over a bowl. Discard the citrus juice. Gently shake the sieve to remove as much liquid as possible. You'll see the shrimp is now a consistent, beautiful pink colour.

Combine everything: In a large mixing bowl, add the drained shrimp, diced red onion, tomatoes, cucumber, and jalapeño. Sprinkle with the salt, pepper, and a pinch of sugar if using. Fold everything together gently with a spatula until evenly distributed. The colours will be incredibly vibrant against the white of the bowl.

Fold in the avocado and coriander: Just before serving, gently fold in the diced avocado and chopped coriander. The avocado adds a lovely, creamy texture that contrasts with the crisp vegetables and firm shrimp. The coriander will release its fresh, herbaceous fragrance.

Rest and serve: Allow the ceviche to rest for 5 minutes at room temperature. This brief rest lets the flavours meld together. Taste and adjust seasoning if needed. Serve immediately while the avocado is still bright green and the vegetables are crisp.