Preheat the oven to 350℉ (175°C). Set the oven rack to the middle position.
Grease and flour (or use non-stick spray) a 9 x 9-inch square pan. Set aside.
In a small bowl, combine the brown sugar with the ground cinnamon and chopped walnuts. Set aside for now.
In a medium mixing bowl, sift or whisk together flour, baking powder and soda. Set aside.
In a large bowl, whisk together the brown sugar with the oil.
To this, add a lightly beaten egg, sour cream, almond extract and lemon zest. Whisk to combine properly together.
Add dry ingredients to the wet ingredients and combine with a wooden or rubber spoon. Do not over mix.
Spoon about half the batter into the prepared pan.
Sprinkle half of the streusel topping evenly over the batter followed by 1 cup of the blueberries. Press the blueberries gently into the batter.
Spread the rest of the batter evenly over the blueberries. Once again, sprinkle the remaining sugar-cinnamon walnut mixture evenly over the top of the batter followed by the blueberries. Press the blueberries gently into the batter. Take a look at the quick video tutorial to see how easy this is.
Bake in a preheated oven for 60 minutes until golden and the cake tester comes out clean.
Place on a wire rack where it can cool down for about 15 minutes.
After this short period, carefully remove the cake from the pan and place it on the wire rack where it will continue to cool down.
Serve cake at room temperature with a dollop of sweet ricotta and a sprinkling of powdered sugar (optional).
Sift the dry ingredients together to better distribute all the individual ingredients throughout the dry mixture. As a result, this process also aerates the flour mixture making the final product lighter in texture.
Do not overmix the batter as this will result in a tough cake.
The sour cream creates an extra moist cake crumb.
Use room temperature ingredients. This creates a smoother batter that results in a cake with a uniform texture. Take out your ingredients one hour before beginning.
Can I use frozen blueberries? Yes, there is no need to thaw. To prevent them from bleeding, run them under cold water and then use paper towels to blot them dry. Tossing them in 1 tablespoon of flour prevents them from sinking to the bottom of the cake. Can I freeze this cake? Yes, this blueberry cake recipe freezes wonderfully for up to 3 months. Once the cake has completely cooled down to room temperature, double wrap with plastic wrap followed by aluminum foil, then, please place it in a large freezer-safe plastic air-tight container to avoid crushing it in the freezer. How to serve? You can serve this blueberry coffee cake as is or with a scoop of ice cream for dessert. As a healthy alternative, consider this sweet ricotta cream instead. It offers a light and velvety texture that tastes great as a topping for baked goods or just a bowl full of berries.Please keep in mind that the nutritional information provided below is just a rough estimate and variations can occur depending on the specific ingredients used.