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. Let the butter soften at room temperature, so it is easily pressed but has not begun to melt. Beat this with an electric mixer's paddle attachment or a wooden spoon until smooth. Add sugar gradually. Beat until the mix becomes lighter in color and expands in volume.. Beat in the following ingredients, one at a time. Scrape the sides of the bowl down after each ingredient is thoroughly mixed. The additional egg white is important for making a cake sturdy enough to support the pineapple, while staying light and fluffy.  2 whole eggs 1 egg white 2 tbsp (30 mL) pineapple juice from the can. (Skip if using fresh pineapple, or substitute lemon juice.) 1 tsp (5 mL) vanilla extract, or the flavoring extract of your choice Sift flour, baking powder, and salt into a separate bowl. Whisk for a few seconds to combine. Add about ⅓ of the flour mixture to the bowl of creamed butter, and beat until no dry lumps remain. Beat in ¼ cup (60 mL) milk. Repeat with another ⅓ of the flour mixture, then another ¼ cup (60 mL) milk, then the last of the flour mixture. Just beat the ingredients until you can't see any dry flour. This batter does not need to be smooth. Spread it out with a knife so the batter covers the fruit completely and evenly. You can do this directly in the skillet used to cook the pineapple. Bake at 350 °F (177 °C) for 45 minutes or until a toothpick inserted into the center comes out clean. If you have a cooking thermometer, the cake is ready when the center reaches 190–200ºF (88–93ºC). Let cool for five minutes, then loosen the edge of the cake with a knife. Put on your oven mitts and place a large serving plate over the skillet. Carefully turn the skillet and plate upside down, then lift the skillet.  Choose a serving plate with a rim, to catch the juices. If the pineapple is left behind on the pan, use a spatula to transfer it back onto the cake. This won't make a difference to the cake's appearance.

Summary:
Cream the butter and sugar Add eggs and pineapple juice. Sift together the dry ingredients. Gradually combine milk, flour, and butter mixtures. Pour the batter over the pineapple. Bake the cake. Let cool and flip upside down.