1. Preheat oven to 325°F (160°C). line a bottom of 8-inch (20cm) round pan with parchment paper and grease the bottom and sides.
2. Prepare date paste: Place dates, water and lemon juice in a small saucepan. Bring to a boil, stirring occasionally. Reduce the heat and simmer for 5-8 minutes, stirring occasionally, until the dates are soft. Remove from heat and set aside.
3. To a large bowl sift flour, baking soda, baking powder and salt. Set aside.
4. In a separate large bowl cream sugar with butter. Add eggs, one at the time, until incorporated. Add tahini paste, date paste, vanilla extract and beat on low speed until fully incorporated. Fold in the flour mixture, 1/2 at the time.
5. Pour the batter into the prepared pan, top with sesame seeds.
6. Bake for 40-50 minutes or until a toothpick inserted in the center of the cake comes out clean. after 30 minutes cover with aluminum foil to prevent over browning. Let cool for 5-10 minutes in the pan, release from the pan and let cool completely.