Heat oven to 350 degrees. Melt butter in 13x9-inch pan in oven. Sprinkle brown sugar evenly over butter. Arrange pineapple slices on brown sugar. Place cherry in center of each pineapple slice and arrange remaining cherries around slices. Press gently into brown sugar.
Add enough water to reserved pineapple juice to measure 1 1/4 cup. Make cake mix as directed on package using oil, eggs, and pineapple juice mixture. Pour batter over pineapple and cherries.
Bake 40 to 45 minutes or until toothpick inserted in center comes out clean. Immediately run knife around sides of pan to loosen cake. Place heat proof serving plate upside-down onto pan; turn plate and pan over. Leave pan over cake 1 minute so brown sugar topping can drizzle over cake; remove pan. Cool 30 minutes. Serve warm or cool. Store loosely covered.
Variation: Omit maraschino cherries and sprinkle pineapple generously with shredded coconut.