Step 1
Preheat oven to 200°C/180°C fan forced and line a square baking pan with aluminum foil or baking paper.
Step 2
Combine flour, 1 cup of sugar, baking powder, salt, and 1 teaspoon of cinnamon in a large mixer bowl. Set aside.
Step 3
Whisk together melted butter and sour cream in another medium-sized bowl.
Step 4
Add vanilla extract and egg to the butter mixture and whisk until well combined.
Step 5
Add wet ingredients to dry ingredients and beat until well combined.
Step 6
Spread about half of the batter into the bottom of the prepared pan.
Step 7
Spread the blueberry jam into an even layer on top of the batter.
Step 8
Crumble the remaining batter and drop over the blueberry jam, forming an even layer.
Step 9
Combine the remaining 1 1/2 teaspoons of cinnamon and 1/4 cup of sugar in a small bowl, then sprinkle over the top of the batter.
Step 10
Bake bars for 20-25 minutes, then remove from oven to cool completely.
Step 11
If you want to add the glaze, combine the powdered sugar, milk, and vanilla extract in a small bowl and whisk until smooth. Drizzle the glaze over the bars.
Step 12
Cut bars into squares. They can be stored at room temperature or in the fridge. I loved them both ways.
