Step 1

Preheat the oven to 350°F. Lightly grease (or line with parchment) a 9” square pan.

Step 2

, To make the streusel: In a medium bowl, stir together the sugars, salt, flour, and spices.

Step 3

, Work in the cold butter until the mixture is evenly crumbly, then stir in the chopped walnuts. Set aside.

Step 4

, To make the cake: In a large bowl or the bowl of a stand mixer, combine the flour, sugar, salt, and baking powder.

Step 5

, Cut the butter into small pieces and add to the bowl of dry ingredients. Beat at low speed until the mixture is sandy looking.

Step 6

, In a separate bowl, whisk together the egg, milk, extracts, and lemon zest. Add the liquid ingredients to the dry ingredients and mix until combined. Note: the batter will be very thick.

Step 7

, Using a spatula, carefully fold the blueberries into the batter.

Step 8

, Spoon the batter into the prepared pan, gently spreading it evenly across the bottom.

Step 9

, Sprinkle the streusel topping over the batter, shaking the pan to distribute it evenly.

Step 10

, Bake the cake for 45 to 50 minutes, until it's brown on top and a toothpick inserted into the center comes out clean.

Step 11

, Remove the cake from the oven and allow it to cool to room temperature, right in the pan, before serving.

Step 12

, Storage information: Store any leftover cake at room temperature, covered, for up to a week. Freeze for longer storage.