Prepare the Cupcakes

1. Preheat your oven to 350°F (175°C). Place paper liners into a standard 12-cup muffin tin.
2. Get a medium bowl. Whisk together the flour, baking powder, baking soda, and salt inside it. Set these dry ingredients aside for now.
3. In a large mixing bowl, use an electric mixer to beat the softened butter and sugar until the mixture looks light and fluffy. This usually takes about three to four minutes.
4. Add the eggs one at a time. Make sure to beat the mixture well after each egg addition.
5. Stir in the vanilla extract, lime zest, and milk. Keep mixing until everything is well combined.
6. Slowly add the dry ingredients you set aside earlier. Gently fold them into the wet ingredients. Be careful not to overmix the batter.
7. Carefully fold the fresh blackberries into the cupcake batter.
8. Spoon the finished batter into the lined cupcake cups. Fill each cup about two thirds full.
9. Bake the cupcakes in the preheated oven for 18 to 20 minutes. You can check if they are done by inserting a toothpick into the center of a cupcake. If it comes out clean, they are ready.

Make the Filling

1. While the cupcakes bake or cool, prepare the filling. In a bowl, beat together the softened cream cheese, powdered sugar, and fresh lime juice. Mix until the filling is completely smooth.

Assemble and Serve

1. Once the baked cupcakes have cooled down completely, use a small knife or coring tool to remove a small center section from each one. Fill the hollowed-out centers with the prepared cream cheese mixture.
2. Top each filled cupcake with a few extra fresh blackberries, a sprinkle of fresh lime zest, and a small slice of lime for decoration.