Roast Mackerel and Potatoes

1. Pre-heat the oven to 350ºF/180ºC. Wash the potatoes and slice them into 1cm thick slices. Put them into a large bowl, grind some salt and pepper over them, add a small handful of thyme leaves, and pour in 3 tablespoons of olive oil. Toss together, then put the potatoes into a roasting pan and roast in the oven for around 40 minutes, until they're golden.

2. Just before the potatoes are ready, take your fish out of the fridge, and lightly salt and pepper the flesh side. In a small bowl, mix together 2 tablespoons olive oil, a tablespoon of the vinegar, another small handful of thyme leaves, and some salt and pepper. When the potatoes are golden, lay the fish skin side up on the potatoes, then spoon over the vinaigrette. Return the pan to the oven, and roast for a further 15-20 minutes, until the fish is cooked through and the skin has begun to visibly crisp up at the edges. Serve with lemon, obvs, and maybe a salad on the side.