Pre-heat the oven to 350°F.
Lightly grease an 8-inch x 4-inch loaf pan; set aside.
In a medium bowl, combine the butter and brown sugar; beat with an electric mixer until light and creamy; add the egg and beat until combined.
In a separate bowl, whisk together the flour, baking powder and salt; set aside.
Pour the juice from the cherries into a 1 cup measuring cup; fill the measuring cup with the milk until it reaches the 1 cup mark.
Alternately, add the flour mixture and cherry milk to the brown sugar mixture; use a whisk and stir just until the flour is absorbed; do not over mix.
Roughly chop the cherries.
Fold the cherries and walnuts into the batter; pour into the prepared loaf pan.
Place in the pre-heated oven and bake for 45 - 60 minutes or until a toothpick inserted in the center comes out clean.
Remove from the oven and allow to cool in the pan, for 10 minutes, before removing to cool completely on a wire rack.