Wash the rhubarb, cut off the ends and and cut into 1-2 cm thick chunks. Halve the vanilla pod lengthwise and scrape out the pulp.

Bring rhubarb, sugar, lemon juice, vanilla pulp and the scraped vanilla pod to a boil in a large saucepan over high heat. Reduce the heat and let it simmer for about 10 minutes. Don't forget to stir!

Meanwhile sterilise the jam jars or atleast rinse them with boiling water. I had my jars and lids cleaned in the dishwasher before, so right before using them again I just fill them with boiling water and leave them like this for about 10 minutes. That's it!

When the rhubarb is soft, stir in the agar-agar (follow package instructions!) and let everything boil for another 5 minutes. Remove the vanilla pulp and carefully put the jam into the jars, making them as full as possible. Seal the jars while hot, turn them upside down and let them cool completely. You can keep the rhubarb & vanilla jam in the fridge for a couple of months.