Prepare the cake:

Preheat your oven to 350°F (175°C). Line a cupcake/muffin tin with paper liners.

In a medium bowl, whisk together the all-purpose flour, baking powder, and salt.

In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Beat in the eggs one at a time, followed by the pure vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, mixing until just combined.

Gently fold in the fresh raspberries into the cupcake batter, being careful not to overmix.

Fill each cupcake liner about two-thirds full with the cupcake batter.

Bake the cupcakes in the preheated oven for 18 to 20 minutes or until a toothpick inserted into the center of a cupcake comes out clean.

Remove the cupcakes from the oven and let them cool in the pan for a few minutes before transferring them to a wire rack to cool completely.

In a small saucepan, add raspberries, lemon juice, and granulated sugar. My raspberries were very sweet, so I did not need much sugar.

Heat over low heat until the raspberries soften and release their juices, stirring and smashing occasionally. Increase heat to medium or medium-low and simmer until the juices evaporate and you are left with a jam that will hold a line on the back of a spoon. Reduce the heat back to low as the jam thickens to keep it from sticking to the bottom and burning.

Strain through a metal sieve to remove seeds into a frozen bowl. No one wants the crunch of raspberry seeds in their buttercream.

Pour into a cold or frozen glass/pyrex bowl and refrigerate until cold. Adding cold jam to the buttercream will keep it nice and thick, and pipeable.

Prepare the buttercream:

Beat the butter in the bowl of a stand mixer fitted with the paddle attachment until lightened and soft.

Slowly add the powdered sugar, followed by the vanilla and salt.

Once the buttercream has come together, add the raspberry puree 2 tablespoons at a time until the desired flavor and consistency is reached.

Place the buttercream in a piping bag and pipe it onto the cooled cupcakes! Top with fresh raspberries or sprinkles.