Method

1. To clean the jars, preheat the oven to 140C/275F/Gas 1. Wash the jars well in warm soapy water then rinse thoroughly under running water. Leave the jars and lids to dry, upside down, in the oven. (Or you can clean the jars by putting them through the hot cycle of a dishwasher.)

2. Place a clean plate in the freezer to chill. This will be used to test if the cooked jam has reached setting point.

3. For the jam, cut the peppers and chillies in half, then remove the seeds and white membranes (keep the white membranes of the chillies if you want more spicy heat). Either chop the peppers and chillies finely by hand or, alternatively, roughly chop them, then place in a food processor and pulse to chop finely.

4. Place the chopped chillies and peppers into a wide, deep saucepan with the sugar, vinegar and tomatoes. Bring slowly to the boil, stirring, until the sugar has dissolved.

5. Bring the mixture to a rolling boil for 7-10 minutes to reduce the liquid by a half. Remove from the heat and stir in the pectin. Return the pan to the heat and boil for another couple of minutes.

6. To test if the jam has reached setting point spoon a little onto the chilled plate. Leave for a moment, then push the edge of the jam with your finger - if the jam is ready the surface will wrinkle as you push.

7. Once the jam has reached setting point, let it cool for five minutes before potting into the sterilised jars. The jam will keep in the sealed jar for up to six months.