PREHEAT & PREPARE: Preheat the oven to 350°F (175°C). Line a 10x15-inch jelly roll pan with parchment paper, leaving some overhang on the sides. Lightly grease the paper.
BEAT THE EGGS & SUGAR: In a large bowl, beat the eggs with granulated sugar and brown sugar using a hand mixer or stand mixer on high speed for 3-4 minutes, until pale, thick, and fluffy.
ADD VANILLA & WET INGREDIENTS: Gently mix in the vanilla extract, vegetable oil, and milk.
SIFT & FOLD: In a separate bowl, sift together the flour, cocoa powder, baking powder, and salt. Gradually fold the dry ingredients into the egg mixture using a spatula, being careful to maintain the batter’s airiness.
BAKE: Pour the batter into the prepared pan, spreading it evenly. Bake for 10-12 minutes, or until the cake springs back when lightly touched.
ROLL IT UP: While the cake is still warm, carefully flip it onto a clean kitchen towel dusted with cocoa powder. Peel off the parchment paper and roll the cake up with the towel, starting from the short end. Let it cool completely.
WHIP THE CREAM: In a chilled mixing bowl, whip the heavy cream with powdered sugar and vanilla extract until soft peaks form.
ADD THE CHOCOLATE: Gently fold in the melted, cooled chocolate until smooth and creamy.
UNROLL & FILL: Gently unroll the cooled cake. Spread the chocolate mousse evenly over the surface, leaving a small border at the edges.
ROLL AGAIN: Carefully roll the cake back up, this time without the towel. Wrap it tightly in plastic wrap and refrigerate for at least 1 hour to set.
PREPARE GANACHE: Heat the heavy cream in a saucepan until hot but not boiling. Pour over the chopped chocolate and let sit for 1 minute, then stir until smooth.
DRIZZLE & DECORATE: Unwrap the cake and place it on a serving platter. Drizzle the ganache over the top, letting it drip down the sides. Decorate with chocolate curls, pastel eggs, and a light dusting of cocoa powder.