Preheat oven to 200oC/Gas Mark 6.
Trim the rhubarb, cut into chunks and microwave or simmer in a pan with 1tbsp water until just tender. Place in an ovenproof dish and stir in 2-3 tbsp sweeter.
Mix the flour and oats together in a bowl. Run in the low fat spread until it resembles breadcrumbs. Stir in the sweeter, then sprinkle evenly over the rhubarb and bake for approximately 45 minutes.