Toast with Smoked Mackerel, Avocado and Green Apple

Bright acidity with rich fish

This toast is all about contrast: the avocado is soft and mild, the mackerel firm and smoky, and the green apple adds juicy freshness and a crisp bite. A tart apple such as Granny Smith stays firm enough to slice thinly and lay on the bread. Apples are generally available year-round; in autumn, there’s often more choice from the season’s harvest. Above all, choose one that tastes tart and fresh and doesn’t feel mealy.

Smoked mackerel has a bold flavour of its own and enough fat to pair well with avocado. Check the fish for any remaining bones as you break it into large flakes. Don’t add extra salt before tasting: the mackerel can be quite salty. Sourdough with a firm crumb holds the topping well. Toast the slices until golden brown so the outside stays crisp beneath the soft avocado and fish.

The dressing is small in volume, but it brings everything into balance. Lemon juice freshens the whole thing, horseradish adds a brief, sharp heat, and dill brings a herby, slightly anise-like note. Stir the dressing well before drizzling it over the toast; otherwise, the horseradish can easily settle at the bottom. Mustard seeds add a subtle nutty flavour and extra crunch. Warming them briefly in a dry frying pan makes them more fragrant. Keep the pan moving and remove the seeds as soon as they start to smell fragrant, before they burn.

Mash the avocado with a fork, but don’t make it completely smooth: a few small pieces add more texture. Toss the apple with some of the dressing just before serving so the slices stay fresh and don’t turn brown. No fresh horseradish on hand? Jarred horseradish works too; start with a small amount and taste, as the heat varies by brand. If you like, swap the dill for finely chopped chives for a milder, oniony flavour.

Serve the toast straight away, with a simple green salad on the side if you like. The quantities are for two substantial slices; for a lighter lunch, you can divide the topping between four smaller slices. Store any leftover mackerel covered in the fridge and follow the storage instructions on the package. Top the bread just before eating: that way, the toast stays crisp and the avocado is less likely to discolour.