1. Preheat oven to 350F (175C).
2. In a large bowl cream the butter and sugar. Add tahini, vanilla extract and syrup or honey. Beat until smooth.
3. Add flour, baking powder and salt. Stir until incorporated. If the dough too soft add 1 tablespoon flour.
4. Refrigerate for 30 minutes.
5. Scoop 1 tablespoon. Shape a ball, then roll in sesame seeds and flatten the cookies into discs.
6. Bake for about 10-12 Minutes or until bottoms and edges are golden. Let cool 10 minutes, then transfer to a wire rack and let cool completely.