Fold a large piece of parchment paper to fit 5" x 6". Slice the butter into thirds then place in the center of the unfolded parchment, fold up the corner to seal it in and roll until a smooth 5" x 6" rectangle. Set aside away from direct heat or sunlight.
Roll out the chocolate chip dough to 11" wide by 7" high on a well-floured surface.
Add the butter rectangle in the center of the dough long ways. Fold in the outer two flaps of the dough and pinch all ends together to seal it in.
Using a rolling pin, gently pound the dough horizontally, then vertically, then gently roll out to 20x10” rectangle. (Review video for visual guide.)
TIP: At all times, make sure the butter stays cold but pliable, and same temperature as the dough. If the butter looks shiny at all, immediately put back in the fridge to firm up.
Brush the surface with cold water, then fold in the two ends like an envelope to meet at the center, then fold again lengthwise like a sandwich. Cover and place on a flat plate to chill in the fridge 30 minutes.
Repeat the process of lightly pounding and rolling out 24×10” rectangle, then folding the exact same way as last time. Except cover and chill 1 hour this time.