Walnut and Brown-Sugar Rugelach

In a food processor, blend butter, cream cheese, granulated sugar, and salt until well combined. Add flour, and pulse just until a dough forms. Divide dough in half; flatten into disks, and wrap each in plastic. Refrigerate until firm, at least 2 hours and up to 2 days, or freeze up to 3 months (thaw before baking).

Preheat oven to 350 degrees, with racks set in upper and lower thirds. Line 2 baking sheets with parchment paper; set aside. In a small bowl, combine egg with 1 teaspoon water to make an egg wash.

Working with one disk at a time, place dough on lightly floured parchment paper, and roll out into an 11-inch circle (about 1/4 inch thick), dusting lightly with flour as needed. Using a large dinner plate as a guide, cut around dough to make a perfect circle; trim off and discard scraps. Brush circles with egg wash; dividing evenly, sprinkle with walnuts and brown sugar.

Using a sharp knife or pizza cutter, cut each circle into 16 equal triangles. Starting from the wide end, roll up each triangle of dough; place on lined baking sheets, seam side down. Brush rolls with egg wash.

Bake until golden brown, 30 to 32 minutes. Transfer rugelach to a wire rack to cool completely.