Preparation: Preheat the oven to 150°C (top and bottom heat). Line a 9-hole cupcake tin with cupcake liners.

Make the Egg Yolk Mixture: Crack 2 eggs into a clean, dry bowl, carefully separating the egg whites and yolks. Set the egg whites aside for later. In a separate bowl, add 40g whole milk and 30g corn oil. Mix them using a hand whisk until fully emulsified, forming a smooth, uniform liquid without visible oil separation. Sift 40g all-purpose flour into the emulsified liquid and gently stir in a Z-shaped motion to avoid overworking the flour. Once the mixture is smooth and free of lumps, add the egg yolks and stir to combine.

Whip the Egg Whites: Add a few drops of white vinegar to the egg whites. Pour in 40g white sugar all at once. Using an electric mixer, begin at low speed until the sugar dissolves, then switch to high speed to whip the egg whites. As you whip, large bubbles will form, and they will gradually become finer. Continue whipping until stiff peaks form, and when you lift the whisk, the egg whites will stand up with small tips.

Combine the Mixtures: Gently take 1/3 of the whipped egg whites and fold it into the egg yolk mixture using a spatula, making light, swift motions from the bottom of the bowl upwards. Be gentle to avoid deflating the egg whites. Once mixed, pour the combined batter back into the remaining egg whites and fold gently until almost fully mixed.

Fill and Bake: Transfer the batter into a piping bag and cut a small hole in the tip. Pipe the batter into the cupcake liners, filling them about 2/3 full. Gently tap the tray on the countertop to release any large air bubbles. Place the tray in the oven and bake at 150°C for 15 minutes. Afterward, reduce the temperature to 140°C and continue baking for another 20 minutes. Keep an eye on the cupcakes—when the surface turns golden and slightly puffs up, they are done.

Cool and Serve: Once baked, carefully remove the tray from the oven using oven mitts. Let the cupcakes cool naturally on a wire rack. For the best texture and flavor, allow the cupcakes to cool completely before serving.