Grease 8-inch baking pan and keep this aside. Preheat the oven to 350 degrees F or 170 degrees C.
Whish the egg whites until foamy. Add sugar in thirds and whisk each time for 30 seconds.
3 Egg, ½ cup Sugar
To the egg yolk, add salt and vanilla extract and mix well. Add 2 tablespoon of whipped egg white mixture from above and mix.
3 Egg, ¼ teaspoon Salt, 1 teaspoon Vanilla extract
Add the egg yolk mixture back to the whipped egg mixture and fold gently until combined.
Next, add the flour in parts and mix until combined
1 cup All purpose flour
Finally, add the oil, and milk, and mix. (at this stage add the color drops or powder if using ). Pour the prepared batter into greased baking pan.
2 tablespoon Oil, 1 ½ tablespoon Milk, ⅛ teaspoon Red color powder or gel, ⅛ teaspoon Yellow color powder or gel, ⅛ teaspoon Green color powder or gel, Blue color powder or gel
Bake in preheated oven for 40 minutes. Remove it from the oven when the toothpick inserted comes out clean.
Let it cool for 10 minutes before removing it from the pan.