Beat the egg white lightly. Add sugar and flour and mix well. Add butter and stir until the paste is smooth.

Add the food color and mix well. Transfer to a piping bag with a small tip.

Place your template one one side of a baking pan and line parchment paper over the template.  I used a 13 x 10 pan.

Using the template as a guideline, pipe the pattern on the parchment paper. Put the pan in freezer for at least 15-20 minutes.

Sift together flour, cocoa powder, baking powder and coffee powder and set aside in a bowl.

Take the egg whites in a large bowl and whip them using a electric whisk until it reaches stiff peaks.

In a bowl, beat egg yolks and sugar until they become pale yellow. To this add the flour-cocoa mixture and fold in.

Add half of the egg white mixture and mix until well incorporated. Then add rest of the egg white mixture and fold in.

Remove the template from the baking tray. Grease the parchment paper to the pan.

Pour the cake mixture and gently spread the cake evenly. Bake in a preheated oven at 180 C | 350 F for 8 minutes.

Sprinkle powdered sugar on  two tea towels. Once the cake is done, flip the cake on the first towel and remove the parchment paper.

Now invert the cake into the second tea towel and immediately roll it with the help of the tea towel, from the side opposite to the pattern.

Place it on a wire rack to cool.

Whip the cream and sugar until stiff peaks are formed.

Chop the strawberries.

Unroll the cake. Spread the cream evenly and sprinkle the chopped strawberries. Gently roll the cake again.