Before starting, preheat the oven to 170ºC/ 340ºF conventional oven. Prepare a 23 cm/9 inch springform pan lined with parchment paper in the bottom.
Sift together the all-purpose flour, cornstarch, baking powder, baking soda and salt and set it aside.
170 g all-purpose flour, 1 tablespoon cornstarch, ½ teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon salt
In a large bowl using an electric hand mixer or in a bowl of a stand mixer, add the butter, and granulated sugar and mix it on high speed for 3 minutes.
90 g butter, 150 g granulated sugar
Add the eggs one at a time into the mixture and mix it in until just combined.
2 large eggs
Continue by adding half the dry ingredients, on low speed, mixing until just combined.
Then add the sour cream, vegetable oil, vanilla extract and mix until just combined. Then add the other half of the dry ingredients and mix until combined.
120 g sour cream, 30 g vegetable oil, 1 teaspoon vanilla extract
Using a rubber spatula, give the batter a gentle fold to make sure all of the ingredients have combined.
Pour the cake into the prepared pan and bake for 28-32 minutes or until a cake tester comes out clean.
Let the cake cool on a cooling rack. After 10 minutes, gently trace a sharp knife along the edge of the pan, to release the cake from the pan, and remove the cake from the cake tin. Let the cake cool down completely.