In a microwave, melt 1/2 cup butter; stir in brown sugar. Spread evenly onto bottom of a greased 5-qt. slow cooker. Sprinkle with cherries and pecans; top with pineapple. Sprinkle evenly with dry cake mix. Melt remaining butter; drizzle over top., Cook, covered, on high until fruit mixture is bubbly, about 2 hours. (To avoid scorching, rotate slow cooker insert one-half turn midway through cooking, lifting carefully with oven mitts.), Turn off slow cooker; let stand, uncovered, 30 minutes before serving. If desired, serve with ice cream.