Beat egg yolks, sugar and vanilla extract until fluffy.
Add in milk and oil. Then stir in flour and baking powder. Set aside.
Whip egg white and vinegar until bubbly.
Then gradually add in sugar until stiff peaks.
Transfer a dollop of the meringue into the egg yolk mixture and mix well.
Combine both mixtures together, folding in gently.
Once combined, divide batter into two and stir in strawberry concentrate into the one of the batters.
Dollop them into a 6 inch chiffon cake pan.
Bake 140 degrees for 45 - 50 mins
Let it cool completely upside down. Then remove from mould and serve.