First Step: Prepare Your Oven and Pan
Preheat your oven to 350°F (175°C). Prepare a jelly roll pan or baking sheet by spraying it with non-stick spray and lining it with parchment paper. Lightly grease the parchment with butter or oil to aid in the cake’s easy release and rolling later.

Second Step: Whip Egg Whites and Sugar
In a medium-sized bowl, beat 4 egg whites on medium-high speed until soft peaks form (about 1-2 minutes). Gradually add one-third cup (65 g) of the granulated sugar and continue beating until stiff peaks form (another 1-2 minutes). Setting aside this meringue creates a stable, airy base for the sponge.

Third Step: Mix Yolks and Wet Ingredients
In a separate bowl, whisk together the 5 egg yolks, 2 tablespoons vegetable oil, 3 tablespoons whole milk, vanilla extract, two-thirds cup (135 g) granulated sugar, and 1 tablespoon lemon zest until combined smoothly. This mixture will enrich the batter with moisture and flavor.

Fourth Step: Combine Dry Ingredients
Sift together 3/4 cup (90 g) all-purpose flour, 2 tablespoons (15 g) cornstarch, 1 teaspoon baking powder, and 1/4 teaspoon fine sea salt in another bowl. This sifted blend ensures a light, fluffy cake texture.

Fifth Step: Fold Ingredients Carefully
Gently fold the dry ingredients into the wet mixture until just combined. Then carefully fold the beaten egg whites into the batter in two additions, mixing only until no streaks remain to keep the airy consistency intact.

Sixth Step: Bake the Sponge
Pour the batter evenly onto the prepared pan and bake for 12-15 minutes or until the cake surface is lightly browned and springs back when touched. This step forms the delicate and soft Swiss-style cake base of the roulade.

Seventh Step: Roll the Cake Warm
Remove the cake immediately from the oven. Dust the top with powdered sugar, invert onto a clean kitchen towel or parchment dusted with powdered sugar, and carefully peel away the baked parchment. While still warm, roll the cake from the short end with the towel/parchment to set its shape and prevent cracking. Allow to cool completely rolled.

Eighth Step: Prepare the Filling
Combine 1 pound (450 g) of sliced fresh strawberries with 1 tablespoon sugar and 1 tablespoon lemon zest in a bowl to macerate and release juices. In a chilled bowl, beat 1 cup (240 ml) cold heavy whipping cream until soft peaks form. Add 1 tablespoon sour cream or 2 tablespoons softened cream cheese, 1/2 teaspoon vanilla extract, and 1/4 cup (30 g) powdered sugar. Beat until stiff peaks form for stable whipped cream filling.

Ninth Step: Assemble the Roulade
Carefully unroll the cooled cake. Spread the whipped cream filling evenly across the surface, leaving about a 1-inch border to avoid overflow. Scatter the macerated strawberries evenly over the cream. Roll the cake tightly back up, this time without the towel or parchment. Wrap in plastic wrap and refrigerate for at least 1 hour to firm up.

Final Step: Serve with Style
Before serving, place the roulade seam-side down on a platter. Optionally dust with powdered sugar or drizzle with melted white or dark chocolate for added flair. Slice into 8-10 pieces and serve chilled for a refreshing, light dessert.