Preheat oven to 350 degrees.
Combine 1/2 cup of sugar with cake flour and sift together 4 times, then set aside.
Place egg whites, salt, and cream of tartar in the bowl of a stand mixer fitted with whisk attachment. Beat on high until the eggs reach medium-firm peaks, about 1 minute. With the mixer on medium speed, add the remaining 1 1/2 cups of sugar, sprinkling it over the beaten egg whites. Whisk for a few minutes until thick and shiny. Whisk in the vanilla and continue to whisk until very thick, about 1 more minute. Sift a 1/4 of the flour mixture over the egg whites and fold it into the batter carefully with a rubber spatula. Continue adding the flour by fourths until it's all incorporated, adding the sprinkles with the last addition.
Pour the batter into an ungreased 10-inch tube pan, smoothing the top with an offset spatula. Bake it for 35 to 40 minutes, until it springs back to the touch. Remove the cake from the oven. Invert the pan on a cooling rack until cool, about one hour. Loosen the cake with an offset spatula around the sides and the inside to carefully remove from pan. Place on platter and serve plain or with freshly whipped cream and berries.