Instructions

• Preheat the oven to 325°F. Prepare a 9-inch springform pan: place a circle of parchment paper in the base and lightly grease the parchment and the sides of the pan. (Do not use a regular 9-inch cake pan — this cake rises higher than most standard pans and may overflow.)
• In a large bowl, whisk the olive oil and the eggs together until well combined and slightly emulsified.
• Add the milk, grated orange zest, freshly squeezed orange juice, and Grand Marnier to the bowl with the oil and eggs. Whisk until evenly combined.
• Add the granulated sugar to the wet mixture and whisk until the sugar is incorporated.
• In a separate bowl, whisk together the all-purpose flour, kosher salt, baking powder, and baking soda to distribute the leavening evenly.
• Add the dry ingredients to the wet ingredients and whisk just until combined. Do not overmix; the batter will be on the thin side.
• Pour the batter into the prepared springform pan. Place the pan on a rimmed baking sheet (to catch any possible leaks) and put it in the preheated oven.
• Bake for about 70–75 minutes, beginning to check for doneness after 60 minutes. The cake is done when the top is golden brown and domed and a toothpick inserted in the center comes out clean or with a few moist crumbs.
• Remove the cake from the oven and let it cool in the springform pan on a wire rack for about 1 hour.
• Release and remove the sides of the springform pan, transfer the cake to the wire rack if it isn’t already there, and allow it to finish cooling. Dust with confectioners’ sugar just before serving.