Light and fluffy angel food cake, filled to bursting with fresh strawberry mousse, offers creamy clouds of berry goodness. Serve just out of the freezer for a cool and creamy summer treat.
Preheat the oven to 325°F. Get out a 10" angel food pan; do not grease the pan as this will inhibit the rise of the cake.
To make the cake: In a small bowl, sift together the flour and confectioners' sugar. Set aside.
Place the egg whites and Bakewell Cream (or cream of tartar) in a large bowl. Whip until foamy at medium speed; this will create lots of smaller bubbles, which are best for structure.
When nice and foamy, slowly add the granulated sugar. Increase the mixer speed to high, and beat for 4 to 5 minutes, until the whites are stiff but not dry — think shaving cream consistency.
Remove the bowl from the mixer and sift one-third of the flour/sugar mixture over the meringue. Add the vanilla and salt; fold everything in gently, until no streaks of flour remain. Repeat with the rest of the flour/sugar mixture, in two more additions.
Transfer the batter into the pan and smooth it into an even layer. Bake for 40 to 45 minutes, or until the top is golden brown and springs back when lightly touched.
Cool the cake upside-down over a bottle (or using the pan's feet) for 2 hours, or until completely cool. (Cooling the cake upside-down will prevent the cake from collapsing.) Loosen the edges of the cake from the pan with a dull knife, and carefully turn it out of the pan. Place the cake in the freezer for 2 hours to firm up before hollowing. Meanwhile, prepare the filling (next step).
To prepare the filling: Place the mashed strawberries, sugar, and gelatin in a microwave-safe bowl. Stir together, then microwave for 1 minute. This will melt and "bloom" the gelatin.
Remove the mixture from the microwave, and chill in the refrigerator for about 30 to 60 minutes, or until thickened.
Place the strawberry mixture in the clean bowl of your mixer and pour in the cream, vanilla, and strawberry flavor. Whip until thick.
To assemble: Turn the cake bottom-side up and cut a channel in the cooled cake with a serrated blade. Be careful not to cut through the bottom of the cake. Use your fingers or a spoon to hollow out the channel, leaving about 1" of cake "wall". Think of it as digging a moat through the center of the cake, leaving inner and outer walls for support.
Dollop the filling in evenly, spreading it over the entire "moat." Fill to the top, then use the remaining filling to cover the entire cake, like frosting. Place the cake back in the freezer for 2 to 3 hours, or up to overnight. The filling will freeze into a lovely semifreddo consistency that will slowly melt as you enjoy your slice of cake.
Serve with strawberry sauce or crushed strawberries mixed with sugar, if desired.
Storage information: Store any leftovers, well-wrapped, in the refrigerator for several days or in the freezer for up to 1 month.
