Caramel Crusted Rhubarb Pudding

This is yet another recipe from the Low Cost cooking class - it's absolutely delicious, and could easily be made with any other fruit you happen to have - adding some apples to the rhubarb, or making it with apples and berries would be nice, I think.

Ingredients:
4 cups diced rhubarb

Crust
¾ cup flour
1 tsp baking powder
½ cup rolled oats
¾ cup sugar
100g melted butter

Topping
¾ cup brown sugar
1 Tbsp cornflour

¼ cup boiling water

Method:
Place rhubarb in ovenproof dish.  Sprinkle crust mixture over rhubarb.  Spoon topping mixture over and pour boiling water over top.  Do not stir.  Bake at 180ºC for 30 minutes until crusty and caramelised.