In a medium bowl, mix the dry ingredients. In a small saucepan, melt the butter and tahini over low heat and stir gently to combine until smooth. Remove the mixture from the heat.
Whisk the date sugar and syrup into the tahini butter mixture. Add the egg and egg yolks and vanilla to the tahini mixture and whisk vigorously until smooth and glossy.
Add the wet ingredients to the dry ingredients and use a flexible spatula to combine until all drys are wet. Don’t overmix!
Scrape batter into the buttered pan, sprinkle with sesame seeds, flaky sea salt and bake for 20-25 mins (or until blondies are golden brown on the top). Allow to cool in the pan, remove and slice into squares. They should be chewy on the inside and puffed on the top!