Whisk the milk, sugar, cornstarch, vanilla, and salt together in a small saucepan. Bring to a full boil over medium heat, whisking often to make sure the bottom doesn’t scorch. When the mixture comes to a boil, remove from the heat, add the tahini, and whisk well until fully incorporated.

Add the chocolate and let the mixture sit, stirring occasionally, until the chocolate is melted. Transfer to two 1-cup Mason jars or mugs, cover with plastic wrap, and chill.

For an extra-rich dessert, whip the cream to soft peaks, dollop onto the pudding, and dust with cocoa powder. Serve cold.