Step 1

Preheat oven to 375°F. Lightly grease a 9-inch square baking pan, set aside.

Step 2

Toss the blueberries in 2 tablespoons of the flour. Set aside.

Step 3

In a large mixing bowl, whisk together the remaining flour, salt, baking powder, baking soda and 1 cup of granulated sugar. Make a well in the center.

Step 4

In a small mixing bowl combine the sour cream, vanilla, milk and eggs. Slowly add the melted butter, stirring to combine. Pour the sour cream mixture into the flour and sugar mixture. Stir with a spatula until the dry ingredients are moistened. The batter will be thick. Gently fold in the blueberries and any extra flour.

Step 5

Pour the batter into the prepared pan and smooth the top. Allow the cake to rest at room temperature while preparing the streusel.

Step 6

Melt the butter in a small bowl in the microwave. Add the flour, cinnamon, sugar and salt. Mix with a fork to combine leaving some large clumps. Sprinkle the topping evenly on top of the cake batter. Take care not to pile too much in the center of the cake or it may sink a bit.

Step 7

Bake the cake at 375°F for 45 - 55 minutes or until a toothpick or knife inserted into the center comes out clean.

Step 8

Cool the cake for at least 10 minutes then serve straight from the pan. If you prefer to serve the cake on a platter, line the baking pan with a sling of parchment paper so the cake can be lifted out of the pan after cooling a bit.