Sift the flour and a good pinch of salt into a mixing bowl, add the diced butter and rub it in with your fingertips, until the mixture resembles coarse breadcrumbs. Gradually stir in enough ice water to make a firm dough.
Turn the dough onto a floured surface and knead lightly. Roll out the pastry and use to line four, 4-inch tart-let tins. Prick the bases with a fork, then chill in the refrigerator for 30 minute.
Line the pastry shells with waxed paper and fill with baking beans. Bake in a preheated oven at 400* for 10 min, then remove the paper and the beans. Return to the oven and bake for another 10 minute.
Place the ricotta, grated onion, Parmesan and mustard in a bowl and beat until soft. Gradually beat in the eggs and yolk.
Gently stir in the crab meat and chopped parsley, then add anchovy paste, lemon juice, salt and cayenne pepper to taste.
Remove the tarts from the oven and reduce heat to 350*. Spoon the filling into the shells and bake for 20 min, until set and golden brown. Serve hot with a garnish of salad greens.