The classic version of this 1970s cake is usually sticky, sweet, and dotted with bright red maraschino cherries. We’ve given it a proper update in our version. Naturally sweet fresh pineapple and whole wheat... pastry flour give our cake a nutritional boost, and the foolproof cake batter is so simple that you can throw it together in minutes, even if you’re low on energy. All the ingredients are beaten together in one bowl, in one go — couldn’t be easier.
Cut the pineapple crosswise into ½-inch-thick pieces.
Grease an 8-inch cast iron skillet or cake pan with 1 tablespoon of butter. Sprinkle with the extra tablespoon of sugar. Arrange the pineapple slices neatly in the pan. Set aside while you make the batter.
Combine the softened butter, sugar, eggs, and vanilla into a large mixing bowl. Sift the flour, salt, and baking powder over the wet ingredients. Beat all the ingredients together with an electric whisk until well blended. If the mixture is stiff, add a little milk to bring the batter to dropping consistency (where a small amount of the batter will fall off a spoon if gently shaken).
Spoon the batter gently over the pineapple with a spatula. Bake on the middle rack in the oven for about 30 minutes or until a toothpick comes out clean.
Let the cake sit for 5 minutes. Run a knife round the edges to loosen it, then set a plate over the top and turn the whole thing upside down. Tap all over the bottom of the baking pan and lift it off the cake. You will have a cake with sticky, caramelized pineapple topping. Serve warm.
A cast iron skillet is the best for making upside-down cakes. They heat evenly.
If your pineapple isn’t quite ripe, leave it in a warm place like the top of your stove for a day so that the sugars start to come up.