1. Preheat the oven to 425° (225 c°). Coat a round pie tin with butter. Chop the rhubarb into 1/2 inch pieces. In a bowl, roll the rhubarb in a 1/2 cup of sugar and the potato flour until coated. Put the rhubarb mix in the pie tin.
Step 2:
2. In a separate bowl, add the flour and a tbs of the sugar. Break the butter into bits and add to the flour and sugar mixture, finely mix the butter into the dry ingredients, forming the ?crumbs?.
Step 3:
3. Add the crumb mix onto the rhubarb.
Step 4:
4. Bake in the middle of the oven for 30 mins, until golden brown. Serve with warm vanilla sauce.
