Mushroom and leek tarts

1.Place flour in small bowl; rub in butter until mixture resembles coarse breadcrumbs. Add mustard, egg whites and enough of the water to make ingredients cling together; knead on lightly floured surface until smooth. Cover; refrigerate about 30 minutes or until firm.

2.Roll pastry between sheets of baking paper until large enough to line six 12cm loose bottom flan tins. Lift pastry into tins; press into sides. Trim edges; place tins on oven tray. Cover pastry with baking paper; fill with dried beans or rice. Bake, uncovered, in moderately hot oven, 10 minutes. Remove paper and beans; bake, uncovered, further 10 minutes or until browned lightly. Cool pastry cases. [Can be made 1 day ahead to this stage and stored in airtight container.]

3.Cook mushrooms in heated, lightly oiled large saucepan until browned lightly and softened. Stir in leek and rosemary; cook, stirring, until leek is soft. Divide mushroom mixture between pastry cases; pour over combined extra egg whites, egg and milk.

4.Bake, uncovered, in hot oven about 25 minutes or until firm.