Lemon Cupcakes with Blackberry Cream Cheese Frosting

and 1/2 cups (190g) all-purpose flour (spoon & leveled)

baking powder

salt

unsalted butter, softened to room temperature

granulated sugar

large eggs, at room temperature

and 1/2 teaspoons pure vanilla extract

milk1

zest + fresh juice of two medium lemons2

fresh blackberries, divided3