1 cup sifted cake flour
10 egg whites, room temperature
1 tsp cream of tartar
1/4 tsp salt
2 tsp vanilla extract
Adjust oven rack to the lowest position and preheat oven to 375 degrees.
Lightly grease two 15 1/2 x 10 1/2-inch jelly roll pans and line them with waxed paper. Grease paper lightly and and sprinkle with flour. Set aside.
Using a blender or food processor, pulverize the granulated sugar to very fine. Sift the flour and half the sugar onto a sheet of waxed paper.
In a large mixer bowl, beat egg whites until foamy then beat in the cream of tartar and the salt. Gradually add the remaining half of the pulverized sugar and beat just until stiff peaks form. Sprinkle in the sugar/flour mixture in three batches, folding each addition just until incorporated. Fold in the vanilla. Spoon half the mixture onto each of the prepared pans. Smooth over the tops with a metal spatula; bake at 375 for 10 minutes. Allow to cool in pans for 5 minutes. Invert onto wire racks that have been covered with waxed paper. Peel off the top sheet of waxed paper. Cool cakes for 15 minutes. Starting on a short end, roll up jelly roll fashion with the fresh waxed paper. Make the COCONUT BUTTERCREAM:
1 can (15-oz) cream of coconut
pinch of salt
1 egg, room temperature
1 egg yolk, room temperature
1 1/4 cups unsalted butter, softened
1/2 tsp vanilla extract
2 cups whipping cream, divided
2 tbsp powdered sugar
2 tsp cornstarch
pinch of salt
1 tbsp amber rum, optional
4 cups shredded coconut, toasted
In a medium saucepan combine the cream of coconut and salt. Simmer the mixture until it is reduced by half (takes about 10 to 15 minutes). Increase heat to medium-high and boil until candy thermometer reaches 230 to 235 degrees, around 5 minutes. Reserve 2 tablespoons of the syrup.
While mixture cooks, beat the egg and egg yolk together in a mixer bowl until very light. Add the remaining hot coconut syrup in a slow, steady stream while beating. Beat until cool, about 5 minutes. Add the butter, one tablespoon at a time. Beat in the vanilla extract.
In a small saucepan, combine 1/2 cup of the whipping cream, powdered sugar, cornstarch, and salt. Bring to a boil over medium heat, whisking constantly. Boil 5 minutes and remove from the heat. Whisk in the rum, if using, and the remaining syrup. Refrigerate until cold, not just chilled.
In a large mixer bowl, beat the remaining whipping cream until stiff peaks form. Whisk in the cream mixture.
To Assemble Rolls:
Unroll the cakes and spread a thin layer of the coconut buttercream over all. Top each with half of the flavored whipped cream. Reroll the cakes. Spread the remaining buttercream over the cakes including the ends. Sprinkle with the toasted coconut, pressing it gently into the buttercream so it adheres. Cover and refrigerate until 30 minutes before serving time.
NOTE: Rolls can be made ahead, wrapped tightly and frozen for up to a week. Thaw, unwrapped, at room temperature.
Yield: 2 rolls of about 10 servings each.