Preheat oven to 375°. Melt butter in a 9- or 10-in. ovenproof skillet. Add brown sugar; mix well until sugar is melted. Drain pineapple, reserving 1/3 cup juice. Arrange about 8 pineapple slices in a single layer over sugar (refrigerate remaining slices for another use). Sprinkle pecans over pineapple; set aside. , In a large bowl, beat egg yolks until thick and lemon-colored. Gradually add sugar, beating well. Blend in vanilla and reserved pineapple juice. Combine the flour, baking powder and salt; gradually add to batter and mix well. , In a small bowl, beat egg whites on high speed until stiff peaks form; fold into batter. Spoon into skillet. , Bake until a toothpick inserted in the center comes out clean, 30-35 minutes (cover loosely with foil if cake browns too quickly). Let stand 10 minutes before inverting onto serving plate. Place cherries in center of pineapple slices.