Preheat the Oven: Start by preheating your oven to 180°C (350°F). Grease and flour your cake pan well to prevent sticking.
Mix the Eggs and Sugar: In a large mixing bowl, beat together the eggs and sugar until the mixture is light and fluffy. This is crucial for achieving that airy texture.
Add Wet Ingredients: Melting the unsalted margarine and allowing it to cool slightly, incorporate it along with the whole milk into the egg and sugar mixture. Stir until everything is well combined.
Combine Dry Ingredients: In another bowl, sift the wheat flour, baking powder, and cornstarch together. This helps to aerate the flour, making your cake even fluffier.
Mix Together: Gradually add the dry ingredients to the wet ingredients, mixing gently until just combined. Be careful not to overmix, as this can toughen the cake.
Bake it Up: Pour the batter into your prepared cake pan, smoothing the top with a spatula. Bake in the preheated oven for approximately 30-40 minutes, or until a toothpick inserted into the center comes out clean.
Cool and Serve: Once baked, allow the cake to cool in the pan for a few minutes, then transfer it to a wire rack to cool completely. Frost or fill as desired before serving!