Combine 1 cup flour, corn starch, sugar, undissolved yeast, and salt in a large mixer bowl with whip attachment in place. Heat milk and butter until very warm (120° to 130°F). Add to flour mixture. Beat 2 minutes at medium speed of electric mixer, scraping bowl occasionally. Add egg and 1 cup flour; beat 2 minutes at high speed. Switch to dough hook attachment. Stir in enough remaining flour to make a soft dough. Continue mixing on low speed for 6 to 8 minutes or hand knead on lightly floured surface until smooth and elastic, about 8 to 10 minutes. Cover; let rest 10 minutes.

On lightly floured surface, roll dough to 16 x 12-inch rectangle. Using a cheese grater shred one third (5 Tbsp) of cold butter on center third of dough; fold ends over butter pressing edges to seal butter in. Turn dough one quarter turn. Repeat rolling, arranging butter, folding and turning procedure twice more. Cover with plastic wrap; refrigerate for 2 hours.(Dough may be held in refrigerator overnight or frozen.)

Divide dough in half. On a lightly floured surface roll each half to a 16-inch circle. Cut each into 8 pie-shaped wedges. Roll up each wedge, beginning at wide end. Place, points down, on 2 non-stick baking sheets. Curve ends to form crescents. Brush with Egg Glaze. Cover; let rise in warm, draft-free place until doubled in size, about 1 hour.