Line a 22 cm loose-bottomed flan tin with pastry and bake blind at 200C for 20 minutes. Reduce oven temperature to 180C.
Boil jerusalem artichokes in lightly salted water until tender, then slice thickly.
Combine all ingredients in a bowl and season. Pour into pastry case and bake for 20 minutes until set and golden on top.
Serve warm with green salad.