Take half the dough, then, roll out to 14×10-in. rectangle. With 4 1/2 in. round cookie cutter, cut out circles; press into 12 muffin cups. Line with foil; fill with pie weights. Freeze about 15 minutes. Bake in bottom third of oven for 10 minutes. Remove foil and weights; let cool for 10 minutes.
Meanwhile, in microwaveable bowl, whisk together cream, flour, egg yolks, sugar, and lemon zest. Microwave at Medium for about 8 minutes or until consistency of pudding, whisking 3 times. Strain into bowl; let cool for 5 minutes.
Pour into shells. Broil 6 inches from heat for 3 minutes. Let cool on rack for 15 minutes. Remove from pan. Refrigerate about 4 hours. Sprinkle with icing sugar.