Spread tahini on bottom of pyrex and around the corners (if you don't have tahini use butter or flour)
Add mixture to pyrex 9x9
Let it sit for a few hours covered on side so baking powder does its job and semolina soaks up the yogurt
After a few hours use a knife to make incisions
Put in oven 350 30-35 minutes uncovered
Syrup
While your dessert is baking, mix sugar, water, lemon, vanilla and butter over medium heat until all sugar is dissolved and you start to form a slightly thickened syrup (it will still be quite watery).