In a small bowl, whisk together the flour, sugar, cornstarch, cinnamon, baking powder, baking soda and salt.
In a separate and slightly larger bowl, whisk together the yogurt, oil, milk and vanilla.
Add the dry ingredients and stir until a smooth batter forms. It’ll be more like a thick cake batter than a biscuit dough, that’s normal.
With a small (2 tbsp) ice cream scoop or spoon, dollop the batter over the surface of the filling. You can also just spread the batter evenly over the entire surface.
Sprinkle the top with turbinado/coarse sugar and bake for about 30 minutes or until the filling is bubbling, the top is golden brown and a toothpick inserted in just the top layer comes out clean.
Let it cool about 5-10 minutes before enjoying with or without ice cream or whipped cream (vegan of course)!