1-Preheat oven and prepare pan: Start by preheating your oven to 350°F (175°C) and lightly greasing a 6-inch round cake pan, then line the bottom with parchment paper for easy removal. This simple setup ensures your cake comes out perfectly every time.

2-Mix dry ingredients: In a medium bowl, sift together the flour and cornstarch, then stir in the baking powder, salt, and baking soda to evenly distribute the leavening agents.

3-Cream butter and sugar: Next, in a large mixing bowl, beat the softened butter and sugar until they turn light and creamy, which takes about 1 minute this step is key for a fluffy texture. Scrape down the bowl to make sure everything mixes well, then beat in the egg and vanilla extract until fully incorporated.

4-Combine ingredients: Gradually add the dry ingredients to the wet mixture, alternating with the buttermilk, and always start and end with the dry ones to keep the batter balanced.

5-Bake the cake: Once mixed, transfer the batter to your prepared pan and smooth the top. Bake for 20 to 25 minutes, or until a toothpick inserted in the center comes out clean.

6-Cool and frost: After baking, let the cake cool in the pan for about 15 minutes, then run a knife around the edge to loosen it and invert onto a cooling rack to cool completely before adding frosting like chocolate buttercream or strawberry cream cheese.