Method
1. Pre-heat oven - 170°C
2. Line a clean muffin pan
3. Add all purpose flour and baking powder to a clean medium bowl
4. Whisk briefly and set aside
5. Add unsalted butter and granulated sugar to a clean large mixing bowl
6. Cream
7. Add vanilla extract to the batter
8. Mix in egg to the batter one by one
9. Transfer dry ingredients to batter
10. Mix until well combined
11. Spoon batter into muffin pan
12. Bake until skewer tests clean - 18 min, 170°C
13. Transfer onto cooling rack until completely cool
14. Add blackberries to a clean small bowl
15. Purée
16. Strain with sieve and set aside
17. Add unsalted butter and powdered sugar to a clean large mixing bowl
18. Mix until well combined
19. Transfer fruit to frosting
20. Mix briefly until combined
21. Spread frosting with cupcakes
22. Garnish with blackberries