1. Preheat the oven to 350 degrees. Line a large baking
sheet with parchment paper or aluminum foil.
2. Combine the nuts, cinnamon, and zest. Beat the
egg whites on low speed until foamy, about 30 seconds.
Add the salt, increase the speed to medium-high, and
beat until soft peaks form, 1 to 2 minutes. Gradually
add the confectioners' sugar and beat until stiff and
glossy, 5 to 8 minutes. Reserve one-third of the meringue
(about 1/3 cup) and fold the nut mixture into the remaining
meringue.
3. Place a large piece of waxed paper on a flat surface
and sprinkle with additional confectioners' sugar.
Place the nut mixture on the sugar, lightly sprinkle
with more confectioners' sugar, top with a second piece
of waxed paper, and roll out 1/4 inch thick. Remove
the top piece of waxed paper. Using a cookie cutter
dipped in water, cut into 2-inch star shapes or use
a sharp knife to cut into diamonds. Reroll and cut
any scraps. Place on the prepared baking sheet.
4. Bake until set, 10 to 12 minutes. Spread the reserved
meringue over the top of the cookies and bake until
the tops are lightly colored, about 5 minutes. Transfer
to a rack and let cool. Zimtsternen taste best if allowed
to stand for 24 hours. Store in an airtight container
at room temperature for up to 3 weeks.