8 egg whites (200 g), at room temperature
1/2 teaspoon cream of tartar
1 cup (115 g) confectioners’ sugar
5/8 cup (88 g) all purpose gluten free flour
1/2 teaspoon xanthan gum (omit if your blend already contains it)
2 tablespoons (18 g) cornstarch
1/4 teaspoon kosher salt
10 ounces canned crushed pineapple in its juice
1/2 teaspoon pure vanilla extract
For serving: pineapple chunks and fat-free whipped topping (optional) (will add an extra WW SmartPoint)
Preheat your oven to 350°F. Lightly grease a 9-inch round cake pan, and set it aside.
In a large bowl with a handheld mixer or the bowl of a stand mixer fitted with the whisk attachment, place the egg whites and beat until foamy. Add the cream of tartar and continue to whip until very soft peaks form (about 2 minutes). Add about 1/4 cup (30 g) of the confectioners’ sugar, and whip until stiff, glossy peaks form. Transfer the egg whites to a separate, clean bowl and set them aside briefly.
In the same large bowl, place the remaining flour, xanthan gum, cornstarch, remaining confectioners’ sugar, and salt, and whisk to combine. Add the crushed pineapple and the vanilla, and beat with the handheld mixer or the paddle attachment of your stand mixer until well-combined. Add the whipped egg whites in 2 or 3 portions, and fold gently into the batter. The first portion of whipped egg whites will deflate more than the remaining one or two. Transfer the batter to the prepared cake pan and smooth the top. The pan will be full.
Place the pan in the center of the preheated oven and bake for 10 minutes. Reduce the oven temperature to 325°F and continue to bake until the cake is mostly firm to the touch in the center (about another 25 minutes). The cake should be risen evenly (not higher at the edges) when you remove it from the oven. Allow the cake to cool for 10 minutes before turning it out onto a wire rack to cool completely. Slice into 9 even slices and serve with fat-free whipped topping and extra pineapple chunks.