Preheat the oven to 350°F (175°C). Coat a 10-cup (2.4 L) Bundt pan really well with nonstick spray. If your pan has deep grooves, make sure to get into every corner.
cooking spray
In a large bowl, sift together the all-purpose flour, cake flour, baking powder, and salt. Set aside.
1½ cups (188 g) all-purpose flour, 1½ cups (165 g) cake flour, 1 tbsp (12 g) baking powder, 1 tsp (6 g) table salt
In the bowl of a stand mixer, beat the vegetable oil, softened butter, confectioners’ sugar, and lemon zest on medium speed until the mixture is pale yellow and fluffy, about 4 minutes.
½ cup (120 ml) vegetable oil, 1 cup (226 g ) unsalted butter, 2¾ cups (330 g) confectioners' sugar, ½ cup (~6 g) finely grated lemon zest
Add the eggs, egg yolks, limoncello, and lemon extract. Beat on medium speed for 1 more minute until fully incorporated.
3 large eggs, 3 large egg yolks, 3 tbsps (45 ml) limoncello , 2 tbsps (30 ml) lemon extract
With the mixer on low speed, add the dry ingredients and heavy cream in three alternating batches, starting and ending with the flour mixture. Mix just until combined and scrape down the sides of the bowl as needed, being careful not to overmix.
¾ cup (180 ml) heavy cream
Scrape the batter into the prepared Bundt pan and smooth the top. Bake on the middle rack for about 60 minutes, rotating halfway through. Check with a toothpick to confirm it’s done.
Let the cake cool in the pan on a wire rack for 30 minutes, then carefully invert it onto a cake stand or serving platter.
While the cake cools, make the syrup: combine sugar, lemon juice, and limoncello in a small saucepan over low heat. Stir until the sugar dissolves, then remove from heat and let cool slightly.
¼ cup (50 g) granulated sugar, ¼ cup (60 ml) fresh lemon juice, 2 tbsps. (30 ml) limoncello
Poke holes all over the warm cake with a skewer and slowly brush the syrup over the surface, letting it soak in.
Once the cake is fully cooled, whisk together the glaze ingredients until smooth. Drizzle over the top and let it run down the sides.
1 cup (120 g) confectioners' sugar, 2 tbsps (30 ml) fresh lemon juice, 1 tsp (5 ml) almond extract
Finish with a sprinkle of toasted slivered almonds and let the glaze set before slicing.
¼ cup (25 g) slivered almonds