Preheat the oven to 175° Celsius.
Coat a metal slice tin with butter. Line with baking paper.
Combine butter, oil, vanilla, zest, juice, egg & egg white in a medium bowl. Stir with a whisk until blended. Gradually add 1 cup sugar, stirring with a whisk until blended. Stir in milk.
In a small bowl, combine flour, baking powder, and salt in a large bowl, stirring with a whisk.
Add milk mixture to flour mixture, stirring it all together. Spoon batter into prepared slice tin.
Toss blueberries in flour to coat, then spread then evenly around the top of the batter.
Combine 2 tablespoons sugar and cinnamon in a small bowl. Sprinkle cinnamon-sugar mixture over top of batter.
Bake at 350° for 35 minutes or until a wooden pick inserted in center comes out clean. Cool completely in pan on a wire rack.