Toast the sesame
seeds in a frying pan over medium heat for 5-7
minutes until lightly browned.
Sift the flour and
salt into a medium bowl. Beat the butter,
confectioners' sugar, and orange zest in a large
bowl with an electric mixer at high speed until
creamy.
Gradually beat in the egg whites. Mix in
the dry ingredients and sesame seeds. Refrigerate
for 1 hour.
Preheat the oven to 350°F/180°C/gas 4.
Butter four cookie sheets. Butter two rolling
pins.
Drop teaspoons of the mixture 2 inches (5
cm) apart onto the prepared cookie sheets.
Use a
thin spatula to spread out the mixture to about 3
inches (8 cm) in diameter. Do not place more than
five cookies on one sheet.
Bake, one sheet at a
time, for 5-6 minutes, or until the edges are
lightly golden. Working quickly, use a spatula to
place the cookies over a rolling pin.
Slide each
cookie off the pin onto a rack to finish cooling.
Butter the cookie sheets again and continue to bake
in batches until all the batter has been used.