Preheat your oven to 350°F (175°C). Line an 8-by-8-inch pan with aluminum foil, making sure to leave some overhang for easy removal later. Spray the foil with cooking spray to prevent sticking.
In a medium microwave-safe bowl, melt the butter for about 60 seconds.
Add the packed brown sugar to the melted butter and stir well to combine.
Crack in the egg and pour in the vanilla extract. Stir again until everything is well combined.
Next, add the flour and salt to the bowl. Gently stir until just combined.
Now, it's time to fold in the chocolate chips and cherries.
Pour the batter into your prepared pan, smoothing it out with a spatula or offset knife.
Place the pan in the preheated oven and bake for 27 to 32 minutes.
Once baked, remove from the oven and let the bars cool in the pan for at least 1 hour.
After cooling, lift the bars out using the foil overhang, slice them into squares, and serve!
