Vegan choc chip cookies with tahini

Name: Vegan choc chip cookies with tahini
Prep time: 15 min
Cook time: 14 min
Total time: 29 min
Cuisine: American
Ingredients: 8 g / 4 tsp ground flax (I use golden flax); 60 ml / ¼ cup soy milk (or other plant milk); 140 g / 5 oz vegan butter block (I use Violife); 100 g / packed ½ cup dark muscovado sugar; 100g / ½ cup caster (superfine) sugar; 60 g / ¼ cup light tahini; 10 ml / 2 tsp vanilla extract; 250 g / 2 cups plain flour (or a good GF flour mix); scant ½ tsp fine salt; ½ tsp baking powder; ¼ tsp baking soda; 100 g / 3.5 oz vegan chocolate; sesame seeds, to coat