1-First step: Get the pans and oven ready Preheat your oven to 180 degrees Celsius or 350 degrees Fahrenheit for 20 minutes. Grease and line 2 x 20 centimeter or 8 inch cake pans. Use pans without loose bases if possible so the batter does not leak. This is a small step, but it saves a huge headache later. While the oven heats, gather every ingredient and bring the eggs to room temperature. If your mixing bowl feels cold, warm it under warm water and dry it well before you start. Room-temperature eggs whip better and give the cake more lift.

2-Second step: Mix the dry ingredients Whisk together the flour, baking powder, and salt in a large bowl. This helps spread the leavening evenly through the flour, so your cake rises more evenly in the oven. If your baking powder has been sitting in the pantry forever, test it first. Fresh baking powder should be active and bubbly when checked with hot water.

3-Third step: Whip the eggs and sugar Beat the 4 eggs on medium speed for 30 seconds. Then slowly add the caster or superfine sugar over about 45 seconds. Keep beating for 7 minutes total until the mixture turns white and triples in volume. This is one of the most important parts of the recipe, because the air you beat into the eggs helps the cake stay light without needing extra fuss later. Do not rush this step. The egg mixture should look thick, pale, and fluffy before you move on.

4-Fourth step: Heat the milk and butter Put the milk and butter in a microwave-safe bowl or heat them together on the stove until the butter melts and the mixture is hot. You want to use it right away while it is still warm. Stir in the vanilla extract and vegetable or canola oil. This hot liquid mixture is what gives the cake its soft, almost velvety crumb. The heat also helps the cake stay moist longer, which is exactly what makes this a true Fail-Proof Cake for day-after-day serving.

5-Fifth step: Add the flour in three lots Add the flour mixture to the whipped egg mixture in 3 additions. Mix on low speed for about 5 seconds each time. Stop as soon as the flour disappears. Overmixing at this stage can make the cake tough, so keep it short and gentle. If you are doing this by hand, a flexible spatula also works well. Fold carefully and scrape the bowl so no dry pockets remain.

6-Sixth step: Temper the hot milk mixture Take a small portion of the batter and mix it with the hot milk, vanilla, and oil mixture. This lightens the liquid so it blends more easily into the main batter. Slowly pour that mixture back into the bowl and mix on low speed for 10 seconds. This step may sound fussy, but it keeps the batter smooth and helps the cake bake evenly. It also prevents the hot liquid from deflating the whipped eggs too much.

7-Seventh step: Fill the pans and bake Divide the batter evenly between the prepared pans. Tap or bang the pans gently on the counter to release large bubbles. This helps avoid tunnels and gives you a smoother crumb once the cake is baked. Bake for about 30 minutes, or until a toothpick inserted into the center comes out clean. Do not open the oven too early, because that can cause the center to sink. If your oven runs hot, check a few minutes earlier. If it runs cool, give it a little more time.

8-Eighth step: Cool the cakes correctly Once baked, let the cakes cool in the pans for 15 minutes. Then turn them out onto wire racks and let them cool completely. This final cooling step can take about 2 hours, and it matters more than people think. Frosting a warm cake can melt the buttercream and make the layers slide around. If you are short on time, you can chill the layers briefly after they are mostly cool, but do not frost a warm cake. That is one of the quickest ways to lose the fluffy texture you worked for.

9-Ninth step: Make the vanilla buttercream Beat the softened butter until smooth and pale. Add the sifted icing sugar in batches so it does not fly everywhere. Pour in the vanilla extract and 2 tablespoons of milk first, then add more milk up to 4 tablespoons as needed until the frosting is fluffy and spreadable. If the frosting is too soft, chill it for a few minutes. If it feels too thick, add a tiny splash more milk. The goal is a smooth, creamy finish that spreads well without tearing the cake.

10-Tenth step: Frost and serve Spread the vanilla buttercream over the fully cooled cake layers. You can frost the top only for a simpler look, or cover the whole cake if you want a birthday-style finish. Slice and serve once the frosting has set a bit. For the best flavor, let the frosted cake sit for 20 to 30 minutes before slicing. The vanilla taste becomes rounder and the crumb feels even softer.