Prepare the Cupcake Batter: In a large mixing bowl, combine all-purpose flour, baking powder, baking soda, and salt. In another bowl, cream together softened butter and granulated sugar until light and fluffy. Mix in eggs, sour cream, whole milk, vanilla extract, and lemon zest. Gently fold in the mashed raspberries, creating a lovely swirl of color.
Bake the Cupcakes: Preheat your oven to 350°F (175°C). Line a cupcake pan with liners and fill each one about two-thirds full with batter. Bake for 18-20 minutes or until a toothpick inserted comes out clean and the tops are lightly golden.
Make the Frosting: In a mixing bowl, beat the softened cream cheese and butter together until light and airy. Gradually incorporate powdered sugar, then mix in lemon juice and lemon zest until smooth and luscious.
Assemble Your Cupcakes: Allow the cupcakes to cool completely before frosting. Generously spread or pipe the creamy lemon frosting onto each cupcake, ensuring every bite is decadent.