Preheat oven to 350°F. Fill a mini muffin tin with paper liners.
In a bowl, combine flour, baking powder and salt. In a mixing bowl, beat together the eggs, sugar and vanilla for about 10 minutes or until the mixture lightens, triples in volume and forms a ribbon when dribbled off a spoon. With the mixer running, drizzle in the oil. Add the dry ingredients alternately with the milk, and beat on low speed until smooth.
Fill paper liners 3/4 full with batter. Bake for 10-15 minutes, until toothpick inserted in the cupcake centre comes out clean. Remove from oven and let cool a few minutes, then transfer cupcakes to a wire rack to cool completely.
Make icing: Beat cream cheese, butter and vanilla until light and creamy. Gradually beat in icing sugar until smooth. (If icing is too runny, add more icing sugar.) Ice cooled cupcakes using a spatula, spreading knife or a piping bag with decorative tip. Garnish with fresh blueberries.
Makes 30 mini cupcakes.