Drain pineapple from can and reserve 2 tablespoons of the syrup.
Melt the butter in a 10 inch cast iron skillet and stir in the brown sugar until well blended. Remove the skillet from the heat and arrange the pineapple slices on top of the sugar mixture. Put a cherry in the center of each slice.
Combine flour and baking powder. In a mixing bowl beat together the shortening and granulated sugar. Beat in the egg, lemon juice and vanilla. Beat in flour mixture and milk until batter is smooth.
Pour cake batter evenly over pineapple in skillet and bake at 350°F for about 40 minutes. Allow the cake to cool for about 5 minutes and then turn onto a serving plate.