Press dough together slightly to form a small rectangle, wrap in plastic wrap and refrigerate while you prepare the filling.
To prepare filling: Grind poppyseeds in a coffee grinder. Place ground seeds in a bowl, cover with boiling water and set aside 30 minutes to soften. Drain seeds into a strainer set with a clean flour sack towel to catch all the seeds, and gently squeeze out the excess water.
In a bowl of a food processor fitted with a metal blade, add raisins and pulse until finely chopped.
In a medium saucepan over medium heat, melt butter. Add poppyseeds, raisins, sugar, milk, honey and almond extract, and bring mixture to a simmer. Cook, stirring occasionally, until filling is slightly thickened and most of the moisture is gone, about 5 to 8 minutes (it will look like a slightly wet paste). Remove from heat and set aside to cool. Add egg white to filling and stir to combine.
To prepare cookies: Preheat oven to 400 degrees and line baking sheets with parchment paper.
Unwrap dough and place on a lightly floured work surface. Cut dough into 3 equal pieces (you will only use 2 of the pieces, unless you make a double batch of the filling; the remaining third can be frozen, or filled with your favorite holiday spread, cheese or meats for a last-minute appetizer; prepare and bake according to the cookie instructions below). Working with one section at a time, using a lightly floured rolling pin, roll dough out to a rectangle, 12 inches long, 8 inches wide and about 1/8-inch thick. Spread half of filling over dough (filling should be about twice as thick as dough), leaving a 11/2-inch border on one of the sides, and a 1/2-inch border on the remaining three sides; for smaller cookies, leave the 11/2-inch border on one of the long sides, and for larger cookies leave the 11/2-inch border on one of the short sides.