Preparation

• Preheat oven to 350 degrees F. Lightly butter or grease the bottom and sides of a 15 by 10-inch jelly roll pan; line with parchment paper.
• To make design paste, mix butter and sugar together until smooth. Add flour and then egg white, mixing until smooth.
• Divide paste into 3 bowls and add food coloring as desired.
• Transfer pastes into piping bags fitted with small round piping tips and pipe design onto parchment.
• Place pan in freezer to set the design while preparing the batter.
• In a mixing bowl, whisk egg yolks with sugar until lightened. Add vegetable oil, milk, almond extract, and salt. Add food coloring if desired.
• Sprinkle sifted cake flour over batter and fold until incorporated.
• In a clean bowl, beat egg whites until frothy. Add remaining sugar and beat until medium-stiff peaks form.
• Fold a third of egg whites into batter, then fold in remaining whites until just incorporated.
• Pour batter over prepared design, spreading into an even layer. Bake for about 10 minutes until springy.
• Invert warm cake onto parchment, reveal design, and dust with powdered sugar. Roll the warm cake carefully in a tea towel.
• Let the rolled cake cool for about 1 hour or until completely cool.
• To make filling, sprinkle gelatin over 1 tablespoon cool water and let soften for 5 minutes. Microwave until dissolved.
• Pulse freeze-dried strawberries with sugar until finely ground. Beat whipping cream until frothy, then add powdered sugar and beat until medium-stiff peaks form.
• Mix a spoonful of whipped cream with gelatin, then fold this mixture into the rest of the whipped cream along with the strawberry sugar mixture.
• Unroll the cake carefully, spread the filling, and roll it up gently. Wrap tightly and refrigerate for at least 2 hours or overnight.
• To serve, slice with a sharp serrated knife for best results, and refrigerate for up to 3 days.