Preheat oven to 350°F. Line a 10×15” or 10.5×15” cake/jelly roll pan with foil and spray with floured nonstick cooking spray.: You should smell the faint warmth of the oven as it comes up to 350°F , and the pan s foil will glint under the kitchen light when ready. Preparing the pan carefully ensures the thin sponge bakes evenly and releases cleanly later on. A common issue is uneven lining, which creates air pockets under the batter and leads to uneven baking; press the foil snugly into corners and coat the foil lightly with the floured spray so the cake won t stick. If your oven has hot spots, rotate the pan halfway through the bake to get an even surface color, avoiding overbrowned edges.
Place eggs in a large bowl or the bowl of an electric mixer. Beat at medium speed with mixer for 5 minutes until foamy and yellow. Add sugar and mix for 2 more minutes, until the mixture is thickened slightly. Mix in oil, baking powder, salt, and vanilla, then add flour and mix slowly until just combined. Pour into prepared pan, spreading as needed with a spatula. Bake for 10-15 minutes, or until the top is browned and the cake springs back when touched lightly. (Mine took 12 minutes, but all ovens differ.): As you beat the eggs , you ll notice their texture shifting from watery to voluminous and pale, with ribbons forming when the whisk lifts, which indicates the right aeration. That airy sponge is what prevents cracking when rolling, so resist the urge to cut the beating time short. A frequent mistake is underbeating which yields a dense batter that tears; if your mixture still looks glossy and not ribbonlike, keep beating in short increments to reach the frothy, pale stage.
While the cake is baking, lay out a clean kitchen towel onto the counter. Spread with about 1/4 cup powdered sugar.: After adding the granulated sugar , the mixture becomes smoother and slightly thicker, and you should be able to see air pockets suspended in the batter. When you fold in the all-purpose flour gently, avoid overmixing to preserve those bubbles. The batter should spread easily across the pan with a spatula, forming a glossy, even layer. Overworking the batter knocks out air and makes the cake heavy, which is the main reason rolls crack during shaping.
Remove the hot cake from the oven and carefully, using oven mitts so you don’t burn yourself, flip the cake onto the towel. This might make a mess, but that’s okay. Carefully remove the pan and foil (they’re hot!) and then, using the towel, roll up the cake from the short side. The towel will be rolled into the cake. Let this cool completely before continuing.: Watch the surface transform from pale to a light golden hue, and lightly tap the center; it should spring back, not stay indented. My oven takes about 12 minutes , but models vary, so use the springback test rather than the clock alone. Undercooking leaves a gummy cake that s hard to roll, while overcooking yields a dry, brittle sponge that cracks, so remove when the springback is just right.
Note: you can wrap the cooled cake in plastic wrap and let it sit overnight before finishing.: Feel the towel s texture and dust it evenly with powdered sugar to create a nonstick layer that helps the cake roll without tearing. This little tactile preparation prevents sticking and adds a hint of sweetness at the seam. A common oversight is uneven sugar coverage, which causes parts of the cake to stick to the towel when flipping; be generous and consistent with the dusting.
Make the filling: place cream cheese and sugar in a large bowl or the bowl of an electric mixer. Use mixer to beat the cream cheese and sugar until it’s smooth and fluffy, then beat in vanilla. Slowly add the heavy whipping cream, then turn the mixer up to high and beat until stiff peaks form. Halfway through mixing, stop the mixer and scrape down the sides and bottom of the bowl. Stir sprinkles into the whipped cream.: When you flip the pan, the cake should come away easily if the foil and spray were done right; you ll hear a soft slide and see the cake s underside exposed. Rolling it while hot traps steam and sets the sponge in a rolled shape as it cools, preventing cracking later. Don t rush unrolling it while hot for filling, or you risk tearing; let it cool fully in the towel so the spiral holds and the filling won t melt on contact.
To fill cake: Carefully unroll the cake. Spread with the whipped cream mixture. Carefully roll the cake back up as tight as possible, unsticking it from the towel as you go. Wrap the cake roll in plastic wrap and chill until ready to top and serve.: you can wrap the cooled cake in plastic wrap and let it sit overnight before finishing. : Resting overnight allows the crumb to relax and the moisture to distribute evenly, which can make slicing cleaner the next day. I sometimes do this when I m prepping for a party, as it actually improves stability, and the cake is easier to handle when slightly firm. The pitfall is overwrapping too tightly with no airflow at all; a light seal is fine to prevent drying without making the texture gummy.
To top: place chocolate chips and heavy whipping cream in a microwave safe measuring cup or bowl. Heat on high power for 60-90 seconds or until the cream is hot, then whisk until smooth. Let cool for 10 minutes. Place cake roll on a wire rack set over a cookie sheet. Pour the ganache over the cake evenly. Top with more sprinkles. Chill until set.: place cream cheese and sugar in a large bowl or the bowl of an electric mixer. Use mixer to beat the cream cheese and sugar until it’s smooth and fluffy, then beat in vanilla. Slowly add the heavy whipping cream, then turn the mixer up to high and beat until stiff peaks form. Halfway through mixing, stop the mixer and scrape down the sides and bottom of the bowl. Stir sprinkles into the whipped cream. : The cream cheese should become silky and without lumps, and when you gradually add cold heavy whipping cream , the mixture transforms into billowy peaks that hold shape. The aroma will be tangy and sweet, and folding in the Christmas colored sprinkles adds visual cheer. A common error is adding the cream too quickly or starting at high speed, which can lead to splattering or uneven whipping; add slowly and increase speed as the mixture thickens.
To fill cake: Carefully unroll the cake. Spread with the whipped cream mixture. Carefully roll the cake back up as tight as possible, unsticking it from the towel as you go. Wrap the cake roll in plastic wrap and chill until ready to top and serve. : The unrolled sponge should feel supple and lightly dusted with powdered sugar , and spreading the filling evenly ensures each bite has balance. Rolling tightly without squeezing out the filling creates a neat spiral; the tactile feel of resistance tells you when it s snug. If the cake resists and feels stiff, chilling briefly makes it more manageable; forcing a too-stiff roll risks cracking, while a too-loose roll will unfurl.
To top: place chocolate chips and heavy whipping cream in a microwave safe measuring cup or bowl. Heat on high power for 60-90 seconds or until the cream is hot, then whisk until smooth. Let cool for 10 minutes. Place cake roll on a wire rack set over a cookie sheet. Pour the ganache over the cake evenly. Top with more sprinkles. Chill until set. : When the chocolate chips melt into the warmed heavy whipping cream , the mixture becomes glossy and pours like silk; whisk until smooth and let it settle slightly so it s not piping hot when poured. The ganache s aroma is rich and chocolatey, and it should cascade over the roll in an even layer. Pouring too-hot ganache can melt the filling, so allow that brief cooling period to preserve texture. Once set in the fridge, the ganache offers a satisfying snap and sheen that finishes the dessert beautifully.