preheat oven to 160 degrees Celsius (320 F)
Line up a pan with a baking sheet
combine all ingredients in a food processor or by hand
Wrap the dough in cling film and refrigerate for about 20 minutes. This step is not necessary but recommended because the dough will be more convenient to work.
(a little more than one inch) make small balls about 2.5 - 3 cm in diameter
Bake in the center of the oven for 15-17 minutes, just until the cookies are golden. Do not let them brown - browning will cause the tahini to lose its flavor.
Remove the cookies from the oven; cool to room temperature.
Sprinkle powdered sugar through a fine sieve.
Store in an airtight container.