• 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.

Prepare the quick jam:

• 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.