Take a mixing bowl and place 3 large-sized egg yolks in it.

Pour 3 tbsp of vegetable oil, 3 tbsp of milk and 1 tsp of vanilla essence into the bowl.

Use a whisk to mix everything until well combined.

Add ½ cup of cake flour and 1 tbsp of cornstarch to the egg yolk mixture.

Whisk again until the texture becomes smooth.

Take an empty bowl and place a strainer on top of it.

Pour the cake mixture through the strainer.

Use a spatula to stir the mixture and gently push it through the strainer into the bowl below. This helps remove any lumps present in the mixture.

Take another bowl and place 3 large-size egg whites in it.

Add ¼ tsp of vinegar to the egg whites.

Using an electric beater, beat the egg whites until it becomes foamy.

Gradually add ¼ cup of sugar in two parts. First, add half of the sugar and beat until well combined. Then pour the remaining sugar and beat until the mixture becomes creamy and firm peaks form.

Transfer a small amount of the creamy egg white mixture into the egg yolk mixture. Gently fold the mixture with a spatula until it gets combined.

Pour the combined mixture into the remaining creamy egg white mixture.

Use a spatula to mix until just combined. Avoid over-mixing to keep the batter light.

Take a baking tray and line the cupcake holes with parchment paper.

Pour the mixture into the baking pan, filling about ⅔ full.

Lightly tap the pan on the counter to release any air bubbles.

Preheat the oven to 130 degrees Celsius or 265 degrees Fahrenheit, bake for 30 minutes, then 150 degrees Celsius or 300 degrees Fahrenheit, and bake for another 5-10 minutes.

After baking, remove the tray from the oven and let them cool in the trays for a few minutes.

Once cool completely, take a bite and enjoy your freshly baked delicious vanilla chiffon cake!