Fill the kettle and boil it. Trim the leek. Slice a cross shape into the top of it. Pull the leaves apart slightly so you can give it a good rinse inside. Shake it dry and thinly slice. Grate or pare the zest from the lemon. Juice it.
Halve the chilli and scoop out the seeds and white bits. Finely chop it. Warm a splash of olive oil in a large pan. Add the leek. Season with salt and pepper. Cook over a medium heat for 5 mins till soft. Stir now and then.
While the leek cooks, crumble the stock cube into a measuring jug. Add the saffron powder. Pour in 650ml hot water from the kettle. Stir till the stock cube dissolves.
Add the chilli, lemon zest and rice to the leek. Stir till the grains are coated in oil. Add a ladleful of the hot stock. Cook over a medium heat, stirring occasionally, till the liquid has been absorbed.
Repeat, adding the stock one ladleful at a time (or just pour in splashes straight from the jug) till the stock has been used up. The rice should be creamy and cooked through – this takes about 25-30 mins.
Make sure the heat under the pan is turned to the lowest possible setting. Rinse the spinach leaves. Stir the spinach into the risotto till it wilts.
Stir in two-thirds of the crab meat. Taste the risotto. Add a splash of the lemon juice and seasoning to taste. Divide the risotto between two warm plates. Top with the remaining crab meat. Serve straight away.