Preheat your oven to 350°F (175°C). Line a 10x15-inch baking sheet with parchment paper and set aside. Gather all ingredients and bring eggs to room temperature.

Step 2 - Separate and Beat Eggs:

Carefully separate egg whites from yolks into two bowls. In the bowl with yolks, whisk together yolks, ube extract, vanilla extract, and melted butter until well combined. Add 1-2 drops of purple food coloring if needed for deeper color.

Step 3 - Prepare Dry Ingredients:

In a separate bowl, sift together flour, cornstarch, and salt. Gently fold the dry ingredients into the egg yolk mixture until just combined. Do not overmix.

Step 4 - Whip Egg Whites:

In a clean bowl, beat egg whites with an electric mixer on medium-high speed until foamy. Gradually add the remaining sugar (about 1/2 cup) while continuing to beat until stiff peaks form, approximately 3-5 minutes.

Step 5 - Combine Wet and Dry Mixtures:

Gently fold the whipped egg whites into the ube yolk mixture in three additions, being careful to preserve the airiness. Fold until just combined with no streaks of white remaining.

Step 6 - Bake the Cake:

Pour the batter into your prepared baking sheet and spread evenly. Bake for 12-15 minutes until the cake is set but still tender. The cake should spring back lightly when touched.

Step 7 - Cool and Prepare for Rolling:

Remove from oven and let cool for 5 minutes. Turn the warm cake out onto a clean piece of parchment paper. Carefully peel away the parchment it baked on. Allow to cool to room temperature.

Step 8 - Make Your Filling:

While cake cools, prepare your filling. For whipped cream filling: whip 2 cups heavy cream with 1/2 cup powdered sugar and 1 teaspoon ube extract until stiff peaks form.

Step 9 - Spread Filling:

Once cake is completely cooled, spread filling evenly over the entire surface, leaving a thin strip (about 1/2 inch) along the top long edge unfilled.

Step 10 - Roll the Cake:

Using the parchment paper to assist you, tightly roll the cake from the bottom long edge, being careful not to squeeze filling out. Roll slowly and steadily for a uniform shape.

Step 11 - Chill and Set:

Wrap the rolled cake in parchment paper and refrigerate for at least 2 hours to allow it to set properly. This chilling time is crucial for clean slicing.

Step 12 - Slice and Serve:

Using a sharp serrated knife dipped in hot water (wiped clean between slices), carefully slice the ube roll cake into individual servings. Dust with powdered sugar if desired and serve chilled.