Blood orange and olive oil upside-down cake

Directions

1. Preheat the oven and prepare the pan: Arrange an oven rack in the center position and preheat the oven to 400°F. Coat the bottom and sides of the springform pan with oil. Line the bottom of the pan with around of parchment paper and smooth it to eliminate air bubbles. Coat the parchment with more oil and set the pan aside.
2. Prepare the blood oranges: Position a blood orange on the cutting board so the “poles” are to your left and right and the fruit is resting on its side rather than upright. Use a sharp knife to cut off one of the poles, exposing a colorful round of fruit. Then slice the fruit as thinly as possible through the widest part, shaving off rounds that are no thicker than ⅛ inch. Reserve the ends for squeezing juice. Remove and discard any seeds from the slices and repeat until all the oranges are sliced (you should have 25 to 30 slices total). Squeeze the reserved ends of the blood oranges into a medium bowl until you have two tablespoons of juice (save any remaining fruit for juicing or another use).
3. Build the upside-down layer in the pan: Add 1/3 cup of the sugar (2.3 oz/ 66g) to the bowl with the juice and whisk until you have a smooth slurry. Pour the slurry into the bottom of the prepared pan and tilt in all directions to spread across the parchment. Arrange the orange slices in an overlapping pattern across the bottom of the pan (see photographs on page 68) and set aside.
4. Mix the dry ingredients: In a medium bowl, whisk the cake flour, semolina, baking powder, and salt to combine and eliminate any lumps.
5. Mix the wet ingredients: In a small bowl, stir together the Grand Marnier, orange  zest, and  orange  blossom water and set aside.
6. Beat the eggs and sugar: In a stand mixer fitted with the whisk attachment (or in a large bowl if using a hand mixer), beat the eggs and the remaining 1 cup sugar (7 oz / 200g), starting on low to break up the eggs and gradually increasing to high, until the mixture is very light, thick, and pale, and it falls off the whisk or beaters back into the bowl in a slowly dissolving ribbon, about five minutes (with a hand mixer, this will take several minutes  longer). See page 23 for a visual of ribbony eggs.
7. Beat in the oil: With the mixer still on high speed, gradually stream in the oil and beat until fully incorporated and the mixture is even thicker (it will be slightly reduced in volume).
8. Alternate adding wet ingredients and dry: Reduce the mixer speed to low and add the flour mixture in three additions, alternating with the Grand Marnier mixture in two additions, beginning and ending with the dry ingredients. After the final addition of flour, stop the mixer and use a large flexible spatula to fold the batter several times, scraping the bottom and sides of the bowl to make sure it’s evenly mixed.
9. Fill the pan and bake: Gently pour the batter over the blood orange slices, making sure not to disturb them, and smooth the top. Transfer the cake to the oven and immediately reduce the temperature to 350°F. Bake until the top is golden brown, the center is firm to the touch, and a cake tester or toothpick inserted into the center comes out clean, 35 to 45 minutes.
10. Cool and unmold the cake: Transfer the pan to a wire rack and let the cake cool for 15 minutes. Run a thin knife around the edges of the cake and remove the outer ring (be careful, as some of the juices from the cake might run). Invert the cake onto a wire rack and remove the circular base. Carefully peel away the parchment and let the cake cool completely. For the best flavor and texture, wrap the cake in plastic and let it sit at room temperature for at least a day before serving.
11. Serve: Slice and serve with sweetened yogurt. 

Note:

1. You can substitute other citrus for the blood orange, such as tangerines or honey mandarins. Just make sure that whatever you use has a relatively thin skin, as thicker-skinned fruit can make the whole cake too bitter.
2. Try to slice the blood oranges as thinly as possible, or else the white pith will not fully soften during baking, not only leaving a bitter taste but also making the cake hard to cut. You want orange slices that are paper thin if possible.
3. Take your time streaming the oil into the egg/sugar mixture to make sure they emulsify, which helps maintain an airy and even texture in the final cake. Too much oil too soon would overwhelm the eggs and cause the mixture to break.

Do ahead:

1. The cake, well wrapped and stored at room temperature, will keep up to five days but is best served on the second or third days.
2. To make a plain olive oil cake, skip the blood orange layer and just remember to omit the 1/3 cup of sugar that would have lined the bottom of the pan with the blood orange juice, only adding one cup to the cake itself. Otherwise, prepare the springform pan in the same way and proceed as written. Right before baking, I recommend sprinkling the top of the batter with more sugar for a sweet crunch. Let the cake cool completely in the pan and then carefully remove the metal ring.

Excerpted from Dessert Person: Recipes and Guidance for Baking with Confidence by Claire Saffitz. Copyright © 2020 Claire Saffitz. Photographs © 2020 Alex Lau. Published in the United States by Clarkson Potter/Publishers, an imprint of the Crown Publishing Group, a division of Penguin Random House LLC, New York. Reproduced by arrangement with the Publisher. All rights reserved.