Preheat the oven to 350 degrees. Grease an 8 by 8 baking pan.

In a bowl, stir together the butter and brown sugar. Add the egg and vanilla. Whisk until smooth.

In a small bowl, mix together the flour, baking powder and salt. Add to the butter and sugar mixture. Fold in the cherries.

Pour the batter into the pan and spread evenly. Bake for 20 to 25 minutes or until top is golden and toothpick comes out clean.

Cool for 20 minutes before cutting into 9 squares.