1-First Step: Prep and mise en place* Preheat the oven to 180°C (350°F) for a conventional oven. If you use a convection oven with a fan, set it to 160°C (320°F).* Grease a 9-inch springform cake pan and line the bottom with parchment paper. This makes it easy to remove the cake after it cools for 15 minutes in the pan.* Gather all ingredients and bring eggs, butter, and milk to room temperature to help them combine smoothly.

2-Second Step: Prepare the orange* Zest the orange directly into a large bowl and set the zest aside. Only zest the outermost orange skin to avoid bitterness from the white pith.* Remove and discard the white pith from the orange. Slice the orange in half and remove any seeds. Blend the orange flesh until smooth. From one large orange, expect about 120 grams of blended orange.

3-Third Step: Mix dry ingredients* Sift together 1¼ cups (150 g) all-purpose flour, ¼ cup (30 g) cornstarch, 1½ teaspoons baking powder, and ¼ teaspoon salt into a bowl. Sifting helps distribute the baking powder and creates a lighter crumb.

4-Fourth Step: Cream fats and sugar* In the bowl with the orange zest, add ⅓ cup (75 g) unsalted butter (room temperature), ⅓ cup (70 g) unflavored vegetable oil, and 1¼ cups (250 g) white granulated sugar. Using a mixer on medium speed, cream these together until light and fluffy, about 2 minutes. The mixture should look pale and aerated.

5-Fifth Step: Add eggs and wet ingredients* Add the 2 large eggs one at a time on low speed, mixing well after each addition so they incorporate evenly.* Add the blended orange, 3 tablespoons (45 g) milk, and 1½ teaspoons vanilla extract; mix on low speed until combined. The batter may look slightly curdled at this stage; this is normal and will correct when you add the dry ingredients.

6-Sixth Step: Combine dry and wet* Remove the mixer attachments and gently fold the sifted dry ingredients into the wet mixture with a spatula. Fold until just combined; do not over-mix or the cake can become dense.

7-Seventh Step: Bake* Pour the batter into the prepared 9-inch springform pan and smooth the top. Gently tap the pan on the counter once to release large air bubbles.* Bake for 35 minutes at 180°C (350°F) conventional, or until a toothpick inserted comes out clean or with a few moist crumbs. Avoid opening the oven door early as sudden temperature changes can make the cake sink.

8-Final Step: Cool and serve* Let the cake cool in the pan for 15 minutes. Run a thin knife around the edges to loosen and remove the outer ring of the springform pan.* Allow the cake to cool to room temperature. Dust with powdered sugar, slice into approximately 12 slices, and serve. The cake can be served plain, with whipped cream, or a light glaze.