This is from the Azores Islands, off the coast of Portugal. In Portuguese, it's called Bolo de Ananás. The cake is most often served for breakfast, but it's sweet enough that it can easily be served as a dessert dish.
Heat the oven to 350°F, and arrange a rack in the middle position. Coat a (9- or 10-inch) spring-form pan with oil or butter, then line the bottom with a round of parchment.
(TIP - To make a parchment circle to line the pan, trace the bottom of the pan on the paper then use scissors to cut the circle.)
Whisk together the almond meal, polenta, flour, baking powder, and salt in a medium bowl; set aside.
In the bowl of a stand-mixer fitted with the paddle (or using a handheld mixer), combine the sugars and eggs and beat on medium-low until just combined, about 30 seconds. Raise the speed to medium and beat until light colored and thoroughly combined and slightly thickened, about another 1 minute. Add the oil and vanilla and mix for an additional 1 minute until well combined and mixture resembles wet sand.
With the paddle still running, gradually add the dry mixture, about 1/2 cup at a time. Stop as soon as you no longer see any dry flour (the mixture should be thick like cornbread batter). Remove the bowl from the stand-mixer and fold in 3 cups of pineapple. Scatter remaining 1 cup of pineapple on the bottom of the pan then spread the batter on top.
Bake until the cake is nicely browned and a or toothpick comes out with just a few crumbs on it, about 50 to 65 minutes (the 9-inch cake pan will take longer to bake). Run a knife along the cake edge, then let it cool completely, at least 1 1/2 hours before removing from pan. Release the spring and invert the cake onto a serving platter or cake stand. Serve topped with a light dusting of powdered sugar.