In another bowl, beat egg, 2 tbsp melted butter and water.
Pour wet ingredients into dry ingredients all at once. Stir together with a clean hand. Once dough is fully combined, turn out onto a floured board and knead until smooth and glossy. Cut dough into thirds. Cover with a towel and let rest 30 minutes.
Brush the UNDERSIDE of a half-sheet baking pan liberally with butter. Press one dough ball into the center of the pan and roll out until it covers about 2/3 of the pan. Carefully stretch dough all the way around the pan, pulling it over the edge and pressing into place.
Bake on the middle rack of a preheated 375°F oven for 10-15 minutes until golden brown. If baking more than one sheet at a time, rotate top-to-bottom and front-to-back halfway through. If baking one sheet at a time, be sure sheet pan is fully cool before prepping the next dough ball. Cool completely on a rack. Break into shapes and serve.