1 kg cleaned strawberries
500 g sugar
1 pouch Želin (or other natural pectin/gelling agent)
Stem the strawberries and wash gently under running water. Leave to drain.
Process with a (hand) blender. (If you prefer “coarse” to “smooth” jam, dice the strawberries using a knife.) Weigh.
Place in a cooking pot and add 400 g of sugar per kilogram of strawberries. Combine the remaining 100 g of sugar with Želin. (Želin is natural pectin that acts as a gelling agent – it helps thicken the jam and shortens the cooking time.)
Cook stirring occasionally for about 30 minutes, skimming the foam constantly (strawberries do create lots of it!). When no more foam is being created, add the sugar and pectin, bring to a boil and cook for few more minutes.
Pour into warmed jars while still hot (fill up to the top!), seal and turn upside down, thus preventing air from entering and spoiling the jam.