• Pre-heat oven at 160° C or 320° F and line baking pan (12 in x 12 in) with parchment paper

Making the cake batter

• Sift cake flour, baking powder, and salt in one small bowl and set aside.
• Using two medium mixing bowls, separate egg white from the yolks. Set aside the egg whites for later use.
• Whisk egg yolk with a wire whisk then gradually add sugar until pale in color. Add the vegetable oil and whisk. Lastly, add the milk and whisk for a couple of seconds.
• Add the cake flour, baking powder, and salt to the egg yolks in 3 batches while whisking. Mix ingredients well until flour is completely dissolved. Set Aside

Making the meringue

• Take the bowl with the egg whites and whisk on high using the whisk attachment, until it becomes foamy. Add the cream of tartar into the bowl and whisk for 2 minutes.
• Decrease the speed to low and gradually add the sugar. Increase speed to high and continue whisking until soft-stiff peaks form for approximately 2 minutes.

Combining the batter and meringue

• Transfer 1/3 of the egg whites to the batter and fold gently. Add the remaining egg whites doing the same folding technique. Transfer batter into the baking pan lined with parchment.
• Bake for 45 minutes or until a toothpick comes out clean. Remove from the oven and flip the cake upside down to a cooling rack and allow to cool completely before removing the parchment paper.

Making the buttercream

• Beat soften butter using a stand mixer or hand mixer until fluffy.
• Add in the granulated sugar and continue mixing until sugar completely dissolves and turns light in color.

Cake assembly

• When the cake cool to touch, cut the edges to remove the browned parts.
• Spread a thin layer of buttercream (approx 3 tbsp) on top making sure it's covered. Add more if needed.
• Cut the cake in half using a serrated knife. Then place the bottom cake on the top part with buttercream spread.
• Evenly spread the remaining buttercream on top and sprinkle with cheese. Bon Appetit!