Jan Hagel (pronounced: yahn hahkel) is a traditional Dutch cookie. I am not Dutch, but I sure know my way around a good cookie. Search "Jan Hagel" and you'll find many recipes varying in thickness as well as choice of nuts. My friends and family like these as thin as I can get them and the tannic walnuts pair well with the sweet crunch. The secret to these gems is in the detailed instructions, which I unselfishly provide. Enjoy! —janet voris
Sift the measured flour and add to butter mixture. Mix until just incorporated but do not overmix.
Pat all of the dough in an ungreased 11x17 (half sheet) pan. This will seem impossible, but just keep working it with your fingers and the heel of your hand until it is even all around.
Mix egg white with 2 tsp water. Brush egg wash lightly and evenly over dough. You will not use all the egg wash.
Sprinkle evenly with all the nuts and press them into the dough a bit.
With a pizza cutter, cut 7 lengthwise strips. Then cut diagonally about the same width as the lengthwise strips to form diamonds. Using a knife, cut the edges that the pizza cutter doesn't reach. The end diamonds will be small and make a nice treat for the cook.
Bake at 325* for 30-40 mins The dough will puff up then deflate and brown. If the edged are quite brown but the dough has not yet deflated, take them out. The dough will deflate as it cools Under some circumstances, the dough does not puff up at all, just browns.
Cool 10 mins then RE-CUT (important) Slide a spatula under the cookies to loosen then let finish cooling in pan.
These store well for several days in a covered container either at room temp or in the fridge. They also freeze well.