Preheat the oven to 170°C and grease the cake pan with butter to prevent sticking.
In a mixing bowl, place the butter and sugar and whisk with an electric mixer for 4-6 minutes until the mixture becomes pale, fluffy, and creamy.
Add the eggs and vanilla essence, then continue mixing on high speed for 3–5 minutes until the mixture looks smooth and well incorporated. The mixture may appear slightly split at this step.
Add the flour, baking powder, and salt, and mix on low speed until just combined; do not overmix.
Pour the batter into the prepared cake pan and bake for 25–30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool completely. Once cooled, cut out a 1–2 inch deep well in the center of the cake, leaving a border around the edges.