Heat the olive oil in a small saucepan over a low/medium heat. Finely dice the onion and add to the pan, sweating gently until tender.
Step 2
Mince the garlic and add to the pan, cooking until tender then add the erythritol and cider vinegar. Stir well to combine, cooking gently until the erythritol has dissolved.
Step 3
Dice the rhubarb into half inch chunks and add to the pan with the ground spices, salt and pepper. Stir well.
Step 4
Bring the mixture to a gentle simmer, cover and cook for 15 minutes until the rhubarb has broken down and you have a thick chutney.