For poppyseed filling, grind poppyseeds and sugar in a food processor. Remove and scrape into a small saucepot. Stir in milk and simmer, stirring often, until milk is absorbed. Stir in butter and vanilla and set aside to cool.
Preheat oven to 375 °F. Toss cranberries with sugar, honey, vanilla and cinnamon. Spread out one sheet of phyllo pastry and brush lightly with butter. Lay another sheet of phyllo on top and brush with butter. Continue layering and brushing phyllo sheets until all are used. Spread cooled poppyseed filling along one long edge of the pastry and spoon cranberry filling over poppyseeds. Starting with the filled side, roll up phyllo pastry to cover filling. Tuck in outside edges of pastry to seal in fruit (like folding a wrap) and continue rolling. Place strudel, seam-side down on a parchment-lined baking sheet. Brush top of strudel with butter and sprinkle with poppyseeds. Bake for 20 to 25 minutes, until pastry is a rich golden brown. Let strudel cool at least 15 minutes before slicing and serving.
Poppyseed Cranberry Strudel is best served warm or at room temperature. Strudel will keep chilled up to three days.