Melt the butter completely before mixing in the sugar, molasses, eggs and vanilla until smooth. Mix in the baking soda and two cups of the flour. Add more flour until dough appears wet but is not terribly sticky.
Refrigerate dough for at least 30 min.
Pre-heat oven to 375° F
Form the chilled dough into balls the size of golf balls. Smash them into the shapes of hockey pucks and place them on parchment-lined baking sheets. This should yield about 18 big cookies, spread across three pans.
Turn on the broiler and broil the tops of the cookies, one pan at a time on a high rack, until golden. Return the oven to 375° on its baking mode, allow the broiler to cool for a moment, then bake the cookies for 10-12 minutes.