Step 1: Preheat your oven to 350°F (175°C). Line a 10×15-inch jelly roll pan with parchment paper, leaving an overhang on the short sides. Lightly grease the parchment paper.
Step 2: In a large bowl, whisk together the sifted cake flour, cocoa powder, baking soda, and salt. Set aside.
Step 3: In another large bowl, using an electric mixer, cream together the softened butter and granulated sugar until light and fluffy, about 2-3 minutes. Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract.
Step 4: In a small bowl, combine the buttermilk and red gel food coloring. Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk mixture, beginning and ending with the dry ingredients. Mix on low speed until just combined; do not overmix. The batter should be smooth and vibrant.
Step 5: Pour the batter evenly into the prepared jelly roll pan and spread it to the edges with an offset spatula. Bake for 12-15 minutes, or until the cake springs back when lightly touched and a toothpick inserted into the center comes out clean. Do not overbake.
Step 6: While the cake is baking, lay out a clean kitchen towel (free of lint) on a flat surface and dust it generously with powdered sugar. Immediately after removing the cake from the oven, invert the hot cake onto the prepared sugared towel. Carefully peel off the parchment paper.
Step 7: Starting from a short end, carefully roll the cake (along with the towel) into a tight spiral. Place the rolled cake, seam-side down, on a wire rack and let it cool completely to room temperature. This trains the cake to hold its shape.
Step 8: While the cake cools, prepare the cream cheese filling. In a medium bowl, beat the softened cream cheese and softened butter together with an electric mixer until smooth and creamy, about 2 minutes. Ensure there are no lumps.
Step 9: Gradually add the sifted powdered sugar, one cup at a time, beating well after each addition until fully incorporated. Mix in the vanilla extract until the filling is light, fluffy, and smooth.
Step 10: Once the cake is completely cooled (this is critical to prevent the filling from melting), gently unroll it. Spread the cream cheese filling evenly over the entire surface of the cake, leaving a small border (about 1/2 inch) on all edges.
Step 11: Starting from the same short end you began with earlier, carefully re-roll the cake, this time without the towel. Roll it tightly but gently. If any filling squeezes out, simply clean it with a small spatula.
Step 12: Wrap the finished red velvet cake roll tightly in plastic wrap and refrigerate for at least 1-2 hours, or preferably overnight, to allow the cake to set and the flavors to meld, making it easier to slice.
Step 13: Before serving, dust the red velvet cake roll generously with additional powdered sugar for a beautiful finish. Use a sharp, thin knife to cut slices, wiping the knife clean between each cut for the cleanest presentation. Enjoy!