Directions

1. Cut the leek in half lengthways and slice into thin half-moons. Wash thoroughly in a colander and drain. (It will look like an enormous amount. Don't worry: it cooks down.)

2. Put the butter, oil and leek into a heavy-based saucepan and grate in the clove of garlic.

3. Turn on medium heat and let the leek cook gently until very soft. It will take about 15 minutes; you don’t have to do anything other than give it an occasional stir and check that it’s not coloring.

4. Meanwhile, pour the stock into a small saucepan. Clamp on a lid and put it over low heat. It needs to be hot, but not boiling, in 15 minutes, so no rush.

5. Once the leeks have collapsed, add the oregano and stir in the rice until the grains are thoroughly coated. Add the blob of mustard and the vermouth, turn the heat up to medium-high and stir until no liquid remains.

6. Pour in about a third of the hot stock and simmer, insistently, until it has been absorbed. Stir often enough to stop it sticking. Add another third, wait for it to be absorbed, and the final third. It should take about 20 minutes.

7. Taste: the rice should be cooked and slightly al dente although but without any chalkiness. If you need to extend the cooking time, add a little water from the kettle.

8. Cut the brie into thick slices and stir through the risotto until melted. Taste again, checking for salt. Serve immediately, grinding over some black pepper with a generous hand and a sprinkle of snipped fresh chives.