mix all the decorative paste ingredients into a smooth paste . fill it up in a piping bag. apply parchment paper on a greased swiss roll baking tray . make pattern as per ur wish .(i made big red dots)
place this tray in freezer for 15-20 minutes .
for roll cake: Using an electric beater whisk egg whites till fluffy, adding sugar gradually. While egg whites are whisking; in a clean mixing bowl combine egg yolks, butter, together with a wire whisk. beat until mixture is creamy Add flour. baking powder & milk into egg yolk mixture until well combined.
Using a wire whisk, combine egg yolk mixture to the stiffly beaten egg whites, slowly and be careful not to over mix as the whites will deflate causing the roll to be dense. now remove the tray from freezer. carefully pour the cake batter in the swiss roll tray .(in one which u made pattern already).
bake in a preheated oven on 180 degrees for 10-12 minutes. Remove cake from oven, leave to cool for 5 minutes.
Flip the cake onto the clean piece of greaseproof paper . Peel the greaseproof paper from the bottom of the cake. Roll cake from the short side into a log and leave to cool completely. Unroll the cake, spread jam and roll into a log again. refrigrate for a while. slice it up & serve.