It is August again, so its time for jamming: this time I have made speculaas greengage jam.

Several years ago I planted a greengage tree in our garden in north-London, and this year, for the first time, I harvested enough greengages to make some jam.

Greengages are a type of pale green plum with sweet, juicy golden flesh. Originally cultivated in France where they are called 'reine claudes' - they were the favourite fruit of my French educated late mother - Anne - to whom I dedicate this recipe.

What follows is an overview of the ingredients that I used to make vandotsch speculaas greengage jam, including:

Makes approximately four jars of jam – I used Bonne Maman jam glass jars (370g)

Ingredients:

- 800g greengages

- 1 teaspoon lemon juice

- 0.15 litre water

- 500g sugar – you can use granulated, white caster sugar or jam making sugar

- 2 teaspoons of vandotsch speculaas spice mix

Directions to make vandotsch speculaas spice greengage jam :

- wash the greaangages thoroughly. Cut out any bruised bits and remove heavily damaged ones.

- Put the fruit in a pan, add the water and bring to the boil

- Simmer for about 35 minutes.

What is pectin?

Jam, jelly and marmalade set because of pectin and it occurs naturally in fruit. When cooked with sugar the naturally occurring acid in the fruit thickens and sets the preserve. Citrus fruit, blackberries, apples and redcurrants have higher pectin levels. Soft fruits are lower. If fruits are low in pectin then fruits with a higher level need to be added. Alternatively, a few squeezes of lemon juice will help them to set. When possible use slightly under ripe fruit when pectin levels will be at the highest.

Because greengages are high in pectin you don't need to add a setting agent. However, as my greengages were quite ripe I still added some lemon juice.

What about the stones in the greengages?

At some stage you will need to remove the stones. Some people prefer to cut the fruits and remove the stones before boiling them. As I was lacking time, I just cut the greengages in four parts and cooked them with their stones. Once I mashed the fruit, I waited for the stones to come to the surface and then I fished them out using a metal strainer.

- add the sugar and lemon juice once the fruit is softened and broken down, stirring continuously until the sugar is dissolved.

How to sterilise glass jars

Now is a good moment to sterilise your glass jars. A clean sterilised jar is essential to the success and longevity of the jams and preserves you spend a lot of time making. It is important to sterilise any jars used for preserves to remove any bacteria, yeasts or fungi to protect the food you put into the jar.

Firstly, heat the oven to round about 130 degrees Celsius. Don't be tempted to turn the oven up any higher, this is a sufficient temperature to sterilise the jars.

Clean and sterilise used jars and lids. Wash them in hot soapy water, rinse again in hot water and place the jars on an oven tray covered with a clean tea towel, making sure the jars are not touching each other. They will expand during heating, keeping them separate prevents them from cracking. Close the oven door and leave the jars for about 30 minutes.

When you are ready to use your hot, sterilised jars, use your oven gloves to remove them from the oven one at a time, putting them onto a heat-proof surface. Fill the jar while the jam or preserve is hot as is the jar.

Jam setting

- after simmering for approximately 35 minutes the liquid should about be ready to set

- before testing for jam setting add the vandotsch speculaas spice mix and stir continuously until it is dissolved. Your kitchen will now start to smell devine!

The method of testing for a good set is to place several dishes in the fridge to chill and at regular intervals take a half teaspoon of the liquid and pour it onto the edge of the chilled dish. Return the dish into the fridge for 1 minute. When the jam is “about right” the liquid will stick to the side of the dish and producing a soft skin that will wrinkle when gently touched. If it doesn’t wrinkle, re-boil the liquid for another 3 minutes and test again.

- when the jam has reached setting point, remove the pan from the heat. Using a ladle, small jar or cup pour the jam while really hot into the warm sterilised jam jars, filling them right to the brim – jam shrinks considerably on cooling). Immediately, put the lid on the jar.

Tip: if you want to increase the shelf life of your jam, put the jars in boiling water for ten minutes

- store your jars in a cool, dry, preferably dark place. Label them. Only store in the refrigerator once opened.

vandotsch speculaas greengage jam is wonderful spooned over Greek yogurt, vanilla ice cream, or, indeed vandotsch speculaas spice ice cream, but the best is probably on well-buttered toast or yesterdays left-over ciabatta, along with a cup of strong coffee at breakfast.