1. Preheat your oven to 350°F (175°C). Grease and line two 8-inch round cake pans with parchment paper on the bottom, then lightly grease the sides to prevent sticking.

2. In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, fine sea salt, and ground cardamom until evenly combined, then set aside.

3. In a large mixing bowl, beat the softened butter and neutral oil together until smooth, then add the granulated sugar and light brown sugar and cream the mixture on medium speed until light and fluffy, about 3 minutes.

4. Add the eggs one at a time, beating well after each addition, then mix in the vanilla extract, fresh orange zest, and fresh orange juice until everything is fully combined, scraping down the sides of the bowl as needed.

5. With the mixer on low, add the dry ingredients in three additions, alternating with the buttermilk, beginning and ending with the dry mixture, mixing just until the batter is smooth and no streaks of flour remain. Do not overmix.

6. Divide the batter evenly between the prepared cake pans, smooth the tops with a spatula, and bake for 25–30 minutes or until the layers are risen, lightly golden, and a toothpick inserted in the center comes out clean or with a few moist crumbs.

7. Let the cakes cool in the pans for 10–15 minutes, then carefully turn them out onto a wire rack, remove the parchment, and allow the layers to cool completely before frosting.

8. To make the frosting, beat the softened cream cheese and softened butter together in a large bowl until completely smooth and creamy with no lumps.

9. Gradually add the powdered sugar, about ½ cup at a time, beating on low until incorporated, then increasing the speed to medium until the frosting is smooth and fluffy.

10. Add the fresh orange zest, 1 tablespoon of orange juice (or milk), and a pinch of ground cardamom if using, and beat until the frosting is silky and spreadable. Add a tiny splash more liquid if needed to reach your desired consistency.

11. To assemble, place one cooled cake layer on a serving plate or cake stand. Spread a thin layer of orange marmalade or orange curd over the top, then add an even layer of cream cheese frosting over the marmalade.

12. Set the second cake layer on top, pressing gently. Frost the top and sides of the cake with the remaining frosting, smoothing it with an offset spatula or creating swirls as desired.

13. Just before serving, sprinkle the top of the cake with chopped pistachios and decorate with thin fresh or candied orange slices. Slice and enjoy slightly chilled or at cool room temperature.