Make topping by combining butter, both kinds of sugar, cinnamon, and salt in a medium bowl. Add flour, nuts, and stir to form a crumbly mixture. For cake, whisk flour, sugar, baking powder, baking soda, and salt. Use an electric mixer to beat in butter until dough is very crumbly.
Beat in egg, egg yolk, milk, and zest to flour mixture. Once batter forms, add blueberries and fold them into the cake batter. Transfer batter to a prepared round or square pan. Sprinkle crumb topping over the top and bake.