Preheat oven to 400 degrees. Position rack in the center of the oven.
In a large bowl whisk together the egg, milk, yogurt, oil, cinnamon and lemon peel.
In a separate bowl stir together the flour, sugar, baking powder and salt. Add to the liquid ingredients, stirring very lightly just until ingredients are moistened.
Gently fold in the blueberries. Spread the batter into an 8- or 9-inch baking pan coated with nonstick spray.
In a small bowl combine the topping ingredients. Sprinkle evenly over the cake batter.
Bake for 30 to 35 minutes or until the top is lightly browned and a wooden toothpick inserted in the center comes out clean.
Allow the cake to cool in the baking pan on a wire rack for at least 10 minutes.
Serve warm or at room temperature.