Preheat oven to 425ºF (220ºC).
Working with half of the dough at a time, roll out to 14-x 10-inch (35 x 25 cm) rectangle. With 4 1/2-inch (11 cm) round cookie cutter, cut out circles; press into 12 muffin cups. Line with foil; fill with pie weights or dried beans. Freeze until hard, about 15 minutes. Bake in bottom third of oven for 8 to 10 minutes or until rims are light gold. Remove foil and weights; let cool in pan on rack for 10 minutes.
Meanwhile, in microwaveable 4 cup (1 L) bowl, whisk together cream, egg yolks, sugar, flour and lemon rind. Microwave at Medium (50%) for about 8 minutes or until consistency of pudding, whisking 3 times. (Or cook in saucepan over medium heat, whisking almost constantly, for about 10 minutes.) Strain into bowl; let cool for
Pour into shells. Broil 6 inches (15 cm) from heat for 3 minutes or until custard has dark brown spots and pastry is browned. Let cool on rack for 15 minutes. Remove from pan. Refrigerate until custard is firm, about 4 hours. (Tarts can be covered and refrigerated for up to 1 day.) To serve, sprinkle with icing sugar.
Yield: 12 tarts