Pre-heat the oven to 180ºC, 160ºC fan, 355ºF, gas mark 4.

Spread the raw peanuts out in a single layer on a preheated baking tray and roast for 15 to 18 minutes until lightly golden inside.

Taste a peanut half (it will be hot so allow it to cool a little). If it has doesn’t have a roasted flavour carry on roasting for a little longer and taste again. This will be the flavour of your peanut butter so it’s important to get it right.

Once the peanuts are ready, allow them to cool.

Meanwhile, sterilise a 0.35 Litre /11.8 US fl oz jar as per notes below. (The recipe makes 400 ml but fits this size).

Pour the roasted peanuts into a food processor (or a high-powered blender) and blend on the lowest setting until the peanuts are chopped to the size you'd like in your peanut butter. Takes about 30 seconds to 1 minute.

For crunchy peanut butter remove 6 tablespoons of chopped peanuts and set aside. For smooth peanut butter skip this step.

Continue blending the peanuts on the highest speed, stopping periodically to scrape down the sides when the mixture seizes (mine needed scraping down twice). Stop blending once the consistency is that of smooth peanut butter (takes about 8 minutes in a food processor).

Finally, remove the blade (if using a food processor) and mix in the chopped peanuts (if making crunchy peanut butter).

Then spoon into a sterilized jar and screw on the lid.

Store in a cool dark place and consume within 3 months.