In a large mixing bowl, cut butter into flour till pieces are the size of small peas.
Sprinkle 1 tablespoon of the water over part of the mixture; gently toss with a fork. Push to side of bowl. Repeat till all is moistened.
Form the dough into a ball and wrap in clear plastic wrap. Chill for 1 hour.
Meanwhile, crumble almond paste into a medium bowl. Stir in sugar and eggs. Let stand for 30 minutes.
Divide dough into 4 equal parts. On a lightly floured surface, roll each portion into a 13x8-inch rectangle. Cut each rectangle lengthwise into 2 equal strips, to make a total of eight 13x4-inch strips.
Stir almond-paste mixture till well combined. Spoon almond mixture evenly down center of each pastry strip. Moisten edges of each pastry strip with water. Fold each long side over filling; seal edges. Pinch seams to seal into logs. Place seam-side down on lightly greased baking sheets.
Brush with the egg white mixed with 1 tablespoon water or just brush with the milk.
Bake in a 425° oven for 10 minutes. Reduce oven temperature to 375°. Bake logs for 10 minutes more or till light brown. Cool on wire racks. Cut each log crosswise into 4 pieces. Makes 32 pastries.
Note: For a smaller batch of pastry, halve all the ingredients and use 1 whole egg and 1 egg yolk in the almond filling. Divide the dough into two equal parts, roll out and cut to make a total of four 13 x 4-inch strips.