Pineapple upside down cake

I've been using this recipe for over 10 years so why change a good thing. Someone requested it so here goes.
1/4 cup stick margarine or butter
2/3 cup packed brown sugar
1 can (20 oz) sliced pineapple in juice, drained
Maraschino cherries
1 1/3 cup all-purpose flour
1 cup sugar
1/3 cup shortening
3/4 cup milk
1 1/2 tsp baking powder
1/2 tsp salt
1 large egg

Preheat oven to 350. Melt margarine in 10 inch ovenproof skillet or square pan, 9x9x2 inches, in oven. Sprinkle brown sugar over margarine, and arrange pineapples over sugar. Place cherry in center of each pineapple slice. Beat remaining ingredients with mixer on low speed for about 30 secs, scraping bowl constantly. Beat on high speed 3 mins, scraping bowl and pour over pineapple. Bake skillet 45 to 50 mins or until toothpick inserted in center comes out clean. Immediately turn upside down onto heatproof plate. Let skillet or pan remain over cake for a few minutes, remove and then enjoy. Q