Preheat the oven to 350 degrees F (175 degrees C). Grease a 12-cup muffin tin or line cups with paper liners.

Combine cake mix, water, oil, and eggs in a large bowl; beat with an electric mixer on low speed for 30 seconds. Increase speed to medium and beat for 2 minutes. Add reserved pineapple juice; beat until combined.

Divide brown sugar, butter, and pineapple tidbits evenly between the muffin cups. Top each cup with 1 cherry. Divide cake batter between the muffin cups.

Bake in the preheated oven until golden and tops spring back when lightly pressed, 15 to 20 minutes.