Line the pie dish with a sheet of pastry and trim the edges. Cover with a piece of parchment, then fill the case with dried beans.
Place the pastry case in the preheated oven and bake blind for 10 to 15 minutes, or till just golden.
Meanwhile, whisk sugar and butter. Add eggs and a couple of spoons of ground almond to mix. Fold the rest of the almonds in with the orange zest and cinnamon. Spoon into the case. Cut the rhubarb into thin lengths and push into the mixture.
Bake for 45 minutes to an hour, depending on your oven, until set.
You can use as much rhubarb as you like; if you love it use the 200g but if like me you like less just use half that amount.