1 bunch slender-stalked rhubarb, trimmed to 300g, cut into 2cm lengths
1 vanilla bean, split, cut in half widthwise
750g caster sugar
2 lemons, juiced
Place strawberries in a sieve and rinse under running water. Hull strawberries, cutting large ones in half, then place in a large bowl with vanilla bean. Scatter over sugar and stir to coat.
Cover and refrigerate, stirring every 2 hours, for 12 or up to 24 hours. (Most of the sugar will dissolve to form a syrup with the strawberry juices.)
Place 3 saucers in freezer to chill. Strain strawberry syrup into a large saucepan, reserving strawberries.
Bring to the boil over high heat, stirring to dissolve any undissolved sugar, then boil for 5 minutes.
Add lemon juice, return syrup to the boil, then add strawberries and rhubarb. Boil for 15 minutes or until mixture reaches setting point.
Cool for 15 minutes, then spoon into warm sterilised jars and seal while hot.