Prep the pan and oven

Line an 8 x 12-inch (20 x 30 cm) rectangular cake pan with a silicone baking mat or parchment paper.

Preheat oven to 325°F (160°C).

In a large mixing bowl, sift together the cake flour and sea salt. Stir to combine and create a well in the center.

In a small bowl, whisk together the milk, vegetable oil, 30 g sugar, and cotton candy extract until blended.

Pour the wet mixture into the well in the dry ingredients.

Whisk gently until just combined and smooth. Do not overmix to avoid developing gluten. Set aside.

In a clean, dry, non-plastic mixing bowl, add the egg whites and beat on low speed until frothy.

Add the cream of tartar and increase speed to medium.

When the whites are opaque and the bubbles have tightened, gradually add the 55 g sugar, a little at a time.

Increase mixer speed to medium-high and beat to soft peaks. Add a few drops of gel food coloring.

Continue beating to stiff peaks (the tip stands straight when the whisk is lifted).

Add the meringue to the flour batter in three additions, folding gently with a spatula each time.

Use broad, sweeping motions, scraping from bottom to top, to keep as much air in the batter as possible.

Pour the batter into the prepared pan and spread evenly with an angled spatula.

Tap the pan firmly on the counter a few times to release large air pockets.

Bake for 10–12 minutes, or until the cake springs back lightly in the center and a skewer comes out clean.

Let the cake cool in the pan for 5 minutes.

Place a cooling rack over the cake pan and invert the cake onto the rack.

Carefully peel off the parchment or mat.

Let the cake cool completely on the rack. The side now facing up will be the outer surface of the roll.

Make the Stabilized Cotton Candy Whipped Cream

Place the mixing bowl, beaters, and cream in the refrigerator until well-chilled.

Add 4 teaspoons water to a small heatproof cup.

Sprinkle 1 teaspoon unflavored gelatin evenly over the water. Let sit for 5 minutes to bloom.

Place the cup in a small saucepan with gently simmering water (do not let water enter the cup).

Heat just until the gelatin is completely dissolved and liquid. Remove the cup and let it cool to lukewarm (not hot).

In the chilled mixing bowl, add heavy cream and sugar.

Whip on medium speed until the whisk starts to leave visible tracks in the cream.

With the mixer running on medium-low, slowly pour in the cooled liquid gelatin in a thin stream, aiming between the whisk and the side of the bowl.

Increase speed to medium-high and whip until stiff peaks form. Do not overwhip.

The cream should be smooth, thick, and pipeable/spreadable. Use right away to fill the cooled cake.

Assemble the Japanese Cotton Candy Swiss Roll

Place the cooled cake on a clean sheet of parchment.

Decide which short side you’ll roll from; that edge will get slightly more cream.

Spread an even layer of cotton candy whipped cream over the cake, leaving a small border at the far short edge.

Add a little extra cream along the short edge that will be rolled first to prevent gaps and cracks.

Using the parchment to help, gently roll the cake starting from the cream-heavy short edge.

Apply light, even pressure as you roll, focusing on keeping the log round rather than extremely tight.

Once rolled, wrap the cake log tightly in plastic wrap.

For a rounder shape, place the wrapped log on a fresh sheet of plastic and roll again, gently shaping into a cylinder.

Refrigerate for at least 1 hour to set.

Before serving, trim a thin slice off each end for a clean look.

Slice into 8 even pieces with a sharp serrated knife, wiping the blade between cuts for neat spirals.