Ingredients 

• 1 large egg (well beaten)
• 2/3 cup granulated sugar
• 1/2 cup canola oil
• 1/2 teaspoon vanilla extract
• 1 1/2 cups all purpose flour
• 2 teaspoons baking powder
• 1/2 teaspoon salt
• 1/2 cup buttermilk
• 1 1/2 cups blueberries (fresh or well-drained)

STREUSEL TOPPING

• 1/2 cup brown sugar
• 1/3 cup all purpose flour
• 1/2 teaspoon cinnamon
• 1/4 cup melted butter
• 1/2 cup chopped walnuts

Instructions 

• Preheat the oven to 350 degrees Fahrenheit.
• In a medium-size bowl, beat together the egg, sugar, oil and vanilla until fluffy.
• In a small bowl, combine the flour, baking powder and salt. Whisk until well combined.
• Add the dry ingredients alternately with the milk. Mix just until combined.
• Fold in the blueberries.
• Spray an 8″ or 9″ square pan with cooking spray.
• Pour the batter into the prepared pan.
• For the topping, combine the brown sugar, flour, cinnamon, butter and nuts. Mix well. Sprinkle the topping over the cake batter.
• Bake for 25-35 minutes. If the pan is a 9″ pan, it will take closer to 25 minutes. If it is an 8″ pan, it will be done in closer to 35 minutes.
• Serve warm.