DIY Hearts Pattern Cake Roll

 Ingredients:

For the Pattern: 

•  1 egg white
•  30 g  castor sugar
•  40 g flour (if making chocolate pattern substitute 20 g with cocoa powder)
•  20 g butter (room temperature)

For the Cake:

• 4 eggs (whites &  yolks separated)
•  - 1 tsp cream of tartar or lemon juice
•  - 1/2 cup + 1 tbsp caster sugar
•  - 60gm melted butter
•  - 1/2 cup flour
•  - 1/4 cup cocoa powder

For the Filling:

•  Your favourite pastry cream
•  Passion fruits/strawberries

Procedures:

For the Pattern:

1. Mix in the egg white, sugar & flour, stir well till blended. Stir in the butter & separate the dough into as many colors as you wanted.
2. Line baking pan (17×11 inches) with parchment paper. Place the design template below the parchment paper on the baking pan. 
3. Using a small round tip piping tube/nozzle, pipe the color dough mixture onto the parchment paper using the template as a guide. 
4. Put the tray in the freezer until ready to use.

For the Cake:

1. Attach whisk attachment. Preheat oven to 200 C. Beat the egg whites till foamy, add cream of tartar/lemon juice. Add the 1/2 cup sugar gradually & beat till stiff peak.
2. In another mixing bowl, whisk egg yolk with 1 tbsp sugar using hand whisk till blended. Fold in the egg white meringue mixture into the yolk mixture in few portions till blended. Do not over mix. Then add in half of the melted butter, half of the flour & half of the cocoa powder & lightly fold into the mixture. Stir the rest of the butter, flour & cocoa powder & mix till incorporated.
3. Take baking tray out of the freezer, pour cake batter over evenly & flat over the tray. Run finger around the edges of the tray to clean up the side. Tap the tray few times & bake at 200 C for about 7 mins.
4. Lightly flour a piece of parchment paper. Remove the cake from the oven & place the top side on the cooling rack. Remove the parchment paper on the pattern side & flip the cake over onto the flour parchment paper.
5. Now with the pattern design side facing down on the parchment paper, spread the fillings. 
6. Roll the cake (roll from one end towards the pattern end) into swiss roll using parchment paper.

References from: where design meets food