Preheat Oven: Preheat your oven to 350°F (175°C). Line a 10×15 inch jelly roll pan with parchment paper.

Prepare the Batter: In a mixing bowl, beat the eggs and granulated sugar together until thick and pale. Add vanilla extract and mix well. Sift together the flour, baking powder, and salt. Gradually fold the dry ingredients into the egg mixture. Add the milk, mixing gently until smooth.

Color the Batter: Divide the batter into two parts. Add a few drops of pink food coloring to one part and mix until the color is uniform.

Bake the Cake: Spread the plain batter evenly in the prepared pan. Drizzle the pink batter on top and use a skewer to swirl the colors gently. Bake for 10-12 minutes, or until the cake springs back when touched lightly.

Roll the Cake: Lay a clean kitchen towel on the counter and dust it with powdered sugar. Turn the hot cake onto the towel, remove the parchment paper, and roll the cake up with the towel. Let it cool completely.

Prepare the Filling: Whip the heavy cream and powdered sugar together until soft peaks form. Gently fold in the strawberry preserves, maintaining a marbled effect.

Assemble the Swiss Roll: Unroll the cooled cake gently. Spread the cream and preserves mixture evenly over the surface. Re-roll the cake without the towel.

Decorate: Cover the rolled cake with whipped cream. Decorate with colorful candy sprinkles and marshmallow decorations if desired.