Preheat oven to 350°F (175°C) and line a cupcake pan with liners.

In a medium bowl, whisk together flour, baking powder, and salt.

In a large bowl, cream butter and sugar until light and fluffy.

Beat in eggs one at a time, then mix in vanilla extract.

Add dry ingredients alternating with buttermilk, mixing just until combined.

Gently fold in raspberries, being careful not to crush them.

Fill liners about two-thirds full.

Bake for 18–20 minutes, or until a toothpick inserted comes out clean.

Cool cupcakes completely on a wire rack.

In a small saucepan, combine raspberries, lemon juice, and sugar.

Cook over low heat, mashing berries as they soften.

Simmer until thick and jam-like, able to hold a line on the back of a spoon.

Strain through a fine sieve to remove seeds into a chilled bowl.

Refrigerate until completely cold.

Beat butter until light and creamy.

Gradually add powdered sugar, then vanilla and salt.

Add cold raspberry puree 2 tablespoons at a time until desired flavor and consistency is reached.

Pipe frosting onto cooled cupcakes and garnish as desired.