Preheat oven to 350°F. Line 2 or 3 baking sheets with parchment paper or silpat mat.

Break almond paste into pieces. Place in bowl of a food processor with the sugar. Pulse into almond paste is crumbled finely, and evenly combined with sugar.

In a separate bowl, beat egg whites to soft peaks. Stir a little of the egg whites into the almond mixture; it will be fairly dry. Fold in remaining whites.

Place almonds in a shallow bowl. Roll almond paste mixture into 1-inch balls, keeping them as round as possible. If mixture is too sticky, alternately drop heaping teaspoonfuls into the bowl of almonds; use your fingers to roll the dough ball around until coated evenly with slivered almonds. Place on prepared baking sheets, spacing 1 inch apart. (I just dumped my almonds into the dough and rolled 1 inch balls.)

Bake cookies until evenly pale gold, 15 to 17 minutes.