Preheat oven to 350°F. Line standard muffin with paper wrappers or reusable silicone cups.
In a small bowl, whisk together flour, baking powder, salt and powdered blueberries. Set aside.
Cream butter, granulated sugar, and optional lemon zest in a stand mixer with paddle attachment. Add eggs one at a time and mix until fully incorporated.
In a measuring cup, combine buttermilk, blueberry and blackberry puree, and vanilla.
Alternate adding flour mixture and buttermilk mixture into creamed butter. Mix until just incorporated.
Divide batter among 12 cupcakes. Bake for 20-24 minutes until cake is done and a toothpick inserted in the center of a cupcake comes out clean. Let cool in tin for a couple of minutes before unmolding and let cool completely on wire rack. Let cool to room temperature before frosting.