Preheat the oven to 350°F/180°C/gas 4. Set out two
cookie sheets.
Sift the flour,
baking powder, and salt into a medium bowl.Beat the butter and sugar in a large bowl with an
electric mixer at high speed until creamy.
Mix in
the dry ingredients and enough water to make a
smooth dough.
Shape the dough into a ball, wrap
in plastic wrap, and refrigerate for 30 minutes.
Shape the dough into balls the size of walnuts.
Put the sesame seeds in a small
bowl and roll
each ball of dough in it.
Transfer to a baking sheet, spacing them 2 inches (5
cm) apart. Flatten the cookies with a fork.
Bake for 10-15 minutes, or until golden brown,
rotating the sheets halfway through for even baking.
Let cool completely.