Yugoslavian Christmas Cookies are 3-layer bar-type cookie baked in a pan with a rich buttery shortbread base, a layer of jam, and a crunchy nutty crumbly meringue topping. They’re elegant, unusual, and surprisingly easy to make.
Cream the butter and sugar together using a hand mixer or stand mixer; add egg yolk and salt and combine. Add flour and combine. The dough will still be crumbly.
Press the dough into the bottom of a jelly roll 11x16-inch pan or a 9 x13-inch pan. Flour your hands to keep them from sticking to the dough if desired.
Make meringue
Using a hand mixer with the whisk attachment, beat the egg whites until stiff. Gradually add 1 cup of sugar. Continue to beat until the meringue is shiny and stiff. Gently fold in ground walnuts and lemon extract.
Assemble and bake
Mix the jam with fork to soften, then spread it evenly over the dough in the pan.
Spread and swirl the meringue over the jam, and sprinkle the top with the chopped walnuts.
Bake for about 40 minutes in the preheated oven, or until the top is golden and crispy.
Cut the cookies in the pan while still warm, using a serrated knife and a gentle sawing motion. Lightly press the broken meringue into the jam layer.