Preheat oven to 375 F. Whisk together all dry ingredients for the tahini crumble until well combined. Stir in tahini, until well combined. Set aside in the fridge while preparing the strawberry and rhubarb filling.
in one mixing bowl, toss rhubarb with 1/3 c sugar. Let sit for 15 minutes. In another bowl, toss strabwberries with 1/3 c sugar. Let sit for 10 minutes.Using a slotted spoon, transfer rhubarb to the strawberry bowl.
Add in cornstarch, lemon zest and juice, vanilla and rosewater to the strawberry and rhubarb mixture. Transfer to the baking dish, making sure the filling is evenly distributed. Top with tahini crumble, breaking larger pieces with your fingers while crumbling on top of the fruit filling.
Bake crisp at 375 for 30 minutes. Reduce oven temperature to 325. Continue to bake for an addtional 20-30 minutes. Topping should be golden brown and the fruit filling should be bubbling. Remove from oven and cool for 20 minutes before serving. Top with ice cream, whipped cream or yogurt. Enjoy!