Preheat oven to 350d. Grease and line an 8x8 pan with parchment paper and set aside.
Add oil, sugar, eggs, yogurt and vanilla to a bowl and whisk to combine.
In a separate bowl combine dry ingredients and whisk to combine. Add dry to wet, whisking till you reach a smooth batter.
Pour the batter into the prepared pan, smoothing it out with an offset spatula.
Make the crumble topping by adding dry ingredients to a medium sized bowl.
Pour melted butter on top and stir to combine. The crumble should hold together when squeezed.
Scatter the top of the cake evenly with the crumble topping.
Place in preheated oven and bake until a skewer comes out clean from the centre of the cake and the cake is golden brown, 30-35 minutes until a toothpick comes out clean from the centre of the cake.
Let the cake rest in the pan for 15 minutes before removing from pan. Carefully transfer cake to a wire rack to cool completely.
While cake is cooling make the glaze. Add glaze ingredients to a small bowl and whisk to combine.
Once cake is cool drizzle the top with the glaze and enjoy!