Skillet Pineapple Upside Down Cake

Preheat oven to 350ºF. Drain can of sliced pineapple into a measuring cup. If juice measures less than 2/3 cup, add water to equal 2/3 cup.
In medium bowl, cream together 4 tablespoons of butter, shortening, and sugar. Add eggs and vanilla extract. Slowly mix in salt, baking powder and flour. Add milk. Add pineapple juice and beat until just combined.
In 12-inch cast iron skillet, melt remaining 4 tablespoons of butter over medium heat. Coat skillet well. Sprinkle brown sugar evenly over the butter. Do not stir.
Let sugar dissolve then turn off heat. Layer pineapple slices over the brown sugar/butter mixture then place cherries in the middle of pineapple slices.
Pour cake batter evenly over the pineapple and gently spread to even out the top. Bake 30-45 minutes until a toothpick inserted into the center comes out clean.