We got this recipe in our Riverford box years ago, it's a favourite of ours. Think it is probably freezable.
BOB'S RECIPES
Spiced Rhubarb Relish
Serves 2-4 as a side, prep 5 mins, cook 15 mins
This is an ideal condiment for a sharp cheese, some fatty roasted pork or whole grilled mackerel
200g rhubarb, cut into 1cm dice
½ small onion, finely diced
1 orange
60ml cider vinegar
100g brown sugar
1 tsp freshly grated ginger
1 star anise
2cm cinnamon stick
pinch of dried chilli flakes (optional)
Heat a little oil in a small saucepan and fry the onions gently for 5 mins until starting to soften.
Meanwhile remove a long strip of zest from the orange with a peeler.
Add the rhubarb to the pan followed by the vinegar, sugar, orange zest, ginger, star anise and cinnamon. If you fancy a bit of heat, add a pinch or two of chilli flakes.
Cook gently until the rhubarb has completely collapsed and thickened; about 10 mins.
Remove the zest, star anise and cinnamon. Add a pinch of salt to season. Use more sugar or a squeeze of the orange juice to sweeten further if it is a little too sharp for your taste.