Preheat the oven to 350 degrees.

In an 8- by 8-inch baking pan, over low heat, melt the margarine. Remove from the heat and stir in the brown sugar. Place the pineapple slices on the sugar mixture, centering the slices closely in the center of the pan so all the pieces are touching. Place a cherry half in the center of each pineapple slice.

In a medium bowl, whisk together the flour, baking powder, and salt.

In another medium bowl, with an electric mixer at medium speed, beat the margarine and granulated sugar until blended, about 1 minute. Add the egg and vanilla and continue beating until smooth, about 30 seconds. The batter will be thin. Add the flour mixture to the batter in thirds, alternating with milk, blending until smooth, 2 minutes. Spoon the batter on top of the pineapple mixture and spread evenly.

Bake until golden brown, about 25 to 35 minutes. Unmold by sliding a thin knife around the cake, pressing against the pan. Invert onto a cake plate. Serve warm.

This recipe yields 12 servings. Serving size: 1 piece.

Exchanges Per Serving: 1 1/2 Fat, 1 Carbohydrate.

Nutrition Facts: Calories 148; Calories from Fat 66; Total Fat 7g; Saturated Fat 1g; Cholesterol 18mg; Sodium 231mg; Carbohydrate 18g; Dietary Fiber 0g; Sugars 8g; Protein 2g.