Vanilla Blueberry Cake with Crumb Topping

Instructions

For the Crumb Mixture:

1. To make the crumb mixture, combine oat flour and sugar in a medium bowl and stir until well combined. 
2. Next, add butter and use a fork to create a crumbly mixture resembling wet sand. 
3. *Note that if you use 1 cup (120g) of all-purpose flour instead of oat flour, you may need to add a bit more butter to achieve the desired consistency. 

For the Cake:

1. Start by lining an 8-inch (20cm) square pan with parchment paper and setting it aside. 
2. Preheat the oven to 350°F (180°C) for approximately 5 minutes before baking the cake. 
3. In a medium bowl, whisk the egg with a wire whisk for about 1 minute. 
4. Add yogurt, melted butter, and vanilla, whisking until thoroughly combined. Set aside. 
5. In a large bowl, sift flour, baking powder, salt, and sugar, whisking to combine the dry ingredients. 
6. Stir the blueberries into the flour mixture until they are well coated. 
7. Add the wet ingredients mixture to the flour mixture, and gently stir with a spatula to form a thick batter, being careful not to overmix. 
8. Spread the batter into the prepared pan, and sprinkle the crumb mixture on top. Lightly press the crumbs down using a spoon. 
9. Bake for about 30 minutes or until the top turns golden brown, and a toothpick inserted in the center comes out clean. 
10. Allow the cake to cool for 5-10 minutes, then remove it from the pan and transfer it to a cooling rack to cool completely at room temperature. 
11. Finally, sift some powdered sugar on top, cut the cake into squares, and serve. Enjoy!