For the Cupcakes:

1. Preheat oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners.
2. Mix the batter. In a large bowl, combine the cake mix, Grape Crush soda, vegetable oil, and eggs. If using, add grape extract and food coloring.
3. Beat the mixture on medium speed for 2 minutes until smooth. Avoid overmixing.
4. Fill the cupcake liners about 2/3 full to allow room for rising.
5. Bake for 18-20 minutes or until a toothpick inserted in the center comes out clean.
6. Cool completely on a wire rack before frosting.

For the Frosting (Optional):

1. Reduce the soda. In a small saucepan, heat ½ cup Grape Crush soda over medium heat until it reduces to ¼ cup. Let cool.
2. Cream the butter. In a bowl, beat the softened butter until light and fluffy.
3. Add powdered sugar gradually, beating after each addition.
4. Pour in the reduced soda and mix until smooth. Add grape extract and food coloring if using.
5. Pipe or spread onto cooled cupcakes.