Mix the blackberries and sugar together in a small saucepan and heat on medium-high until the berries break down and the juiced become thick and syrupy. Set aside to cool.

Preheat the oven to 350 degrees F. Line a muffin tin with cupcake liners.

Mix together the flour, baking powder, and salt together in a medium bowl and set aside.

In a mixer, beat together the butter and sugar until light and fluffy.

Beat in the zest and extract and the eggs one at a time, mixing well between each egg and beating for one additional minute after the last egg.

Alternate between adding the flour and the buttermilk, beginning and ending with the flour. Mic until just combined.

Evenly distribute the batter among the cupcake liners. Spoon a heaping teaspoon of the blackberry jam over the cupcake batter and swirl in using a skewer or knife.

Bake for about 17 - 20 minutes, or until a light golden brown and the tops spring back when gently pressed upon. Take out the oven and allow to cool completely.

Beat the butter until smooth and cream. Beat in the powdered sugar one cup at a time. Mic in the remaining ingredients and beat well.

Fit a piping bag with a large open star tip and fill with the frosting. Frost each cupcake, Stir in the water into the remaining jam and then drizzle the jam over the frosting. Serve. Cupcakes make last up to five days at room temperature in an airtight container.