Heat the oven to 340°F/170°C. Grease a 10-inch round cake pan and line the bottom with parchment paper.
Make the crumb topping: Combine the cold butter, sugar, and flour in a food processor. Pulse until coarse crumbs form. Set aside.
Make the cake batter: In the bowl of a stand mixer fitted with the whisk attachment, combine the flour, baking soda, baking powder, sugar, canola oil, milk, eggs, softened butter, sour cream, vanilla, and salt. Mix until smooth and slightly thick.
Pour the batter into the prepared pan. Scatter the blueberries over the top, then sprinkle evenly with the crumb topping.
Bake for about 45 minutes, until lightly golden and a toothpick inserted into the center comes out clean.
Let the cake cool, then dust with powdered sugar. Slice and serve.
