Preheat the oven to 350 degrees F.
Make sure the egg whites are at room temperature before using. Sift together the flour, 1/2 cup of the sugar and salt, repeating the sifting process 3 times. Yes this is a pain, but necessary.
Add the egg whites to the bowl of your stand mixer fitted with the whisk attachment. Beat on medium speed until frothy, then add in the cream of tartar and vanilla extract. Beat on medium-high speed until soft peaks form. Gradually add in the remaining sugar a few tablespoons at a time, beating until incorporated.
Remove the bowl from the stand and using a spatula, slowly fold in the flour mixture in two or three additions. Do not stir – use the spatula to turn over the egg whites consistently until the flour is incorporated.
Spoon the batter into the pan, evenly the top off with a spatula. Bake the cake for 35 to 40 minutes, or until golden on top and spongy. Immediately invert the cake and allow it to cool completely.
To make the coconut whipped cream, make sure the cans have been refrigerated overnight. Turn them upside down, open the cans and pour out the liquid (you don’t need it for this recipe, I keep it for smoothies, etc), leaving you with the thick cream in the can. Add it to the bowl of your electric mixer and using the whisk attachment, beat it on medium-high speed until thick and creamy. I do not add any extra sugar, but feel free to do so if you’d like.
Gently slice the angel food cake into three layers using a large serrated knife. The coconut cream is thick, so take a spoon and spatula and using small amounts, frost the top of each layer (I use a very line layer of coconut cream) and then add the other layer of cake. When the cake is assembled back to it’s normal shape, begin frosting the outside. I like to do a thin coat on the outside edges and a thicker coat on the top.
I find that it’s best to frost the cake close to serving time, but I do like to refrigerate it for about 30 minutes before serving. Slice the cake into wedges and serve with the grapefruit syrup for drizzling on top.