How to Make It
Preheat the oven to 350°. Generously coat a 10-inch Bundt pan with nonstick cooking spray and dust the pan with all-purpose flour. Sift the 1 1/2 cups of all-purpose flour and cake flour into a medium bowl, along with the baking powder and salt.
In the bowl of a standing mixer fitted with the paddle, use your fingers to rub the sugar with the lemon zest until the sugar resembles pale yellow wet sand. Add the canola oil and cooled butter and beat at medium speed until blended, about 1 minute. Beat in the whole eggs, egg yolks, rum and lemon extract until just incorporated, about 1 minute. Reduce the speed to low and beat in the heavy cream and the dry ingredients in 3 alternating batches, starting and ending with the dry ingredients; be sure not to overbeat. Scrape down the side of the bowl and fold the batter until it is blended.
Scrape the batter into the prepared pan and use a spatula to smooth the surface. Bake in the middle of the oven for about 1 hour, rotating the pan halfway through, until a toothpick inserted in the center of the cake comes out clean. Let the cake cool on a rack for 30 minutes.
In a small saucepan, combine the sugar with the lemon juice and rum and bring to a boil. Simmer over moderate heat, stirring, until the sugar dissolves, about 3 minutes. Let the lemon syrup cool slightly.
Invert the cake onto a wire rack set over a baking sheet. Using a wooden skewer, poke holes evenly all over the cake and brush with the lemon syrup. Let the cake cool completely.
In a medium bowl, whisk the confectioners' sugar with the lemon juice and almond extract until smooth. Pour the glaze over the top of the cake, letting it drip down the sides. Sprinkle the almonds on top and let the glaze set, about 20 minutes. Cut the cake into wedges and serve.