For the dough:
10-1/2 ounces (2-1/3 cups) unbleached all-purpose flour
1/4 cup granulated sugar
1/2 teaspoon table salt
8 ounces (1 cup) cold unsalted butter, cut into 10 pieces
8 ounces cold cream cheese, cut into 10 pieces
For the filling:
6 tablespoons raspberry or apricot jam
For the topping:
1 large egg
1 tablespoon water
1/4 cup finely chopped salted pistachios (1-1/4 ounces)
Make the dough:
Put the flour, sugar, and salt in a large (11-cup or larger) food processor. Pulse briefly to blend the ingredients. Scatter the butter and cream cheese pieces over the dry ingredients. Pulse until the dough begins to come together in large (about 1-inch) clumps.
Divide the dough into four pieces and on a lightly floured surface, knead each until smooth. Shape each into a flat 6x3-inch rectangle and wrap in plastic wrap. Refrigerate until well chilled, about 1-1/2 hours. (The dough may be refrigerated for up to 3 days or frozen for 1 month before proceeding with the recipe.)
Shape and fill the cookies:
Working with one piece of dough at a time, roll the dough on a piece of lightly floured plastic wrap into a rectangle slightly larger than 5 x13 inches (if refrigerated overnight, let sit at room temperature until pliable enough to roll). Dust with additional flour as needed. Using a sharp knife, trim off the ragged edges to make a 5x13-inch rectangle. Position the dough with one long edge facing you. Using a metal spatula (offset is best), spread evenly with 1-1/2 tablespoons of the jam. Using the plastic wrap as an aid, roll up the dough jelly roll-style beginning with one long side. Wrap in plastic and refrigerate until firm, at least 1 hour. Repeat with remaining dough and jam.
Top and bake the cookies:
tip Make a half-batch of dough if your food processor is small. Position racks in the top and bottom thirds of the oven and heat the oven to 350ºF. Line two cookie sheets with parchment or nonstick baking liners. In a small bowl, mix the egg and water with a fork until blended.
Unwrap one roll and set on a cutting board. Using a serrated knife and a ruler, cut the roll into 1-1/4-inch-wide pieces. Arrange cookies seam side down 1 inch apart on the cookie sheets. Repeat with the remaining rolls. Lightly brush the tops with the egg mixture (you won’t need it all) and sprinkle with the chopped pistachios. Bake until the rugelach are golden brown, 28 to 30 minutes, swapping the cookie sheets’ positions about halfway through. Let cool on the sheets for about 20 minutes. Transfer to a rack to cool completely.
Make Ahead Tips
The filled dough logs can be wrapped well and frozen for up to 1 month. Thaw overnight in the refrigerator before proceeding with the recipe.