Move your oven rack to the middle position. Preheat the oven to 350 °F/177 °C.

Line the bottoms of two 8” (not non-stick) cake pans with a circle of parchment paper. Don’t add anything (oil, flour, or paper) to the sides of the pan.

Mix together room temperature water, oil, and egg yolks in a measuring cup with a fork until homogenous in color. Set that aside.

In a mixing bowl, sift in the cake flour, Dutch-processed cocoa powder, white granulated sugar (for flour), and baking powder. Add the kosher salt and whisk for about 30 seconds.

Make a small well in the middle of the flour mixture and slowly pour in the water mixture while whisking to prevent lumps. Stop whisking just when all the flour has been incorporated.

In another clean mixing bowl, add the egg whites and cream of tartar. Pour the white granulated sugar (for meringue) into a small bowl.

Beat the egg whites on medium-high speed until thick and foamy. Gradually add the sugar while whisking until you reach stiff and glossy peaks.

Take a spatula-sized scoop of meringue and stir it into the batter to lighten it. Then fold in the meringue in thirds until fully incorporated.

Evenly distribute the batter into the prepared pans. Bake for about 30-35 mins.

During the last 5 mins of baking, watch the tops of your cake. They will rise high, then shrink down to almost the level of the pan.

Check with a skewer or the internal temp of the cake (around 205-210 °F/96-99 °C).

Move the pans to a wire rack and let them sit for about 3-5 minutes. Flip the cakes out onto a cooling rack and peel off the parchment bottom.

Make sure they are completely cool before assembling and/or frosting.