Add butter; beat and set aside. In a large mixing bowl, place the 4 cups of flour and the chilled butter.
Cut butter into flour until pieces are the size of beans (not too small). Pour the liquid batter into the flour mixture; stir until moistened.Cover the bowl with plastic wrap.
Refrigerate for at least 4 hours or overnight. Remove from refrigerator.
Press into a compact ball on a floured board and divide into 4 parts.
Roll each into a circle 12" or 16".Cut each circle into 6 or 8 pie-shaped wedges.
For each croissant roll a wedge towards the point.Shape into a crescent and place on ungreased baking sheet. Let rise at room temperature until doubled.(May take 2 hours or more). Brush each with egg beaten with cold water.
Preheat oven to 400 F.
Place croissants in oven.
Lower temperature to 350 F and bake for 15 - 20 minutes until golden.