Pastry:
8 oz. Flour
4 oz. Butter
4 tbs. Cold Water

Filling:
2 Bunches Rhubarb
4 tbs. Sugar
Grated Zest of 1 Orange

Topping:
3 oz. Flour
3 oz. Dark Brown Sugar
3 oz. Caster Sugar
3 oz. Butter
3 oz. Walnuts (chopped)
1 tsp. Cinnamon.

Cut the butter into little dice and rub into the flour until like crumbs.
Add the water and knead together lightly to make the pastry.
Roll this out to line a 12″ tart tin. Cover with tin foil and some baking beans
(or whatever) and bake blind at Gas 5/190C/375F, for 15 to 20 mins.

Cut the Rhubarb into small pieces and either cook on a gentle heat with the orange zest and sugar until soft (but not mushy) or do it in a bowl in the microwave.
If it has produced a lot of juice drain some of it off.

For the topping:
Rub the butter into the flour, then stir in the other ingredients (or just throw the whole lot into a food processor and process lightly)

To assemble:
Spoon the rhubarb mixture onto the pastry base and then sprinkle over the crumble mix.
Turn the oven up to Gas 6/200C/400F, and bake for 20 to 25 mins until it looks brown and crisp.
Best served warm with whipped cream.