Position a rack in the center of the oven and heat the oven to 350°F. Butter a 10x2-inch round cake pan or 10-inch cast-iron skillet.
Combine 6 Tbs. of the butter with the brown sugar in a small saucepan and cook over medium heat, whisking until the butter is melted, the sugar is dissolved, and the mixture is smooth, 1 to 2 minutes. Remove from the heat and immediately pour the mixture in the bottom of the prepared pan, tilting to evenly cover the surface.
Set one pineapple ring in the center of the pan. Surround it with several other rings, packing them tightly or even overlapping them slightly. Cut the remaining rings in quarters or sixths and fill in the spaces around the perimeter of the pan. Set a pecan half, curved side down, in the center of each pineapple ring. If you like, fill in any additional spaces with pecan halves, curved sides down. (You may not need all the pecans.)
Finely grind the toasted pecan pieces in a food processor but don’t overprocess or you’ll make pecan butter. In a small bowl, sift together the cake flour, baking powder, nutmeg, and baking soda. Add the salt and ground pecans, mix well, and reserve.
In a stand mixer fitted with the paddle attachment, beat the remaining 8 Tbs. butter with the granulated sugar on medium speed until fluffy, 2 to 3 minutes. Beat in the eggs one at a time, pausing to scrape the bowl. Mix in the vanilla. On low speed, alternate adding the dry ingredients and the buttermilk in five additions, beginning and ending with the dry ingredients, scraping the bowl once or twice, and mixing until the batter is smooth. Pour the batter over the fruit and spread it evenly with a spatula.
Bake until the cake is golden brown and springs back when pressed lightly in the center with a fingertip, 40 to 45 minutes. Transfer the cake to a rack and cool in the pan for 15 minutes. Run the tip of a paring knife around the edge of the cake. Cover with a serving plate, and gripping both the cake and the plate, invert the two. Carefully lift off the cake pan, rearranging the fruit if necessary. Allow the cake to cool completely before serving.
nutrition information (per serving):
based on 12 servings, Calories
20, Fat Calories
180, Saturated Fat
3, Monounsaturated Fat
43, Polyunsaturated Fat
Photo: Scott Phillips