Preheat oven to 350F and set aside an UNGREASED 9" tube pan.
Sift the flour 4-5 times into a medium bowl then add 3/4 cup of sugar and the sprinkles. Use a fork to incorporate.
Place the egg whites in a bowl of a standing mixer add the cream of tartar and vanilla extract and beat on medium until frothy. About 2 minutes.
Measure 3/4 cup of sugar (150 g ) and sprinkle 1 TBS of sugar at a time (counting to 10 before adding the next) into the mixer while mixing.
Keep mixing until a shiny stiff meringue has formed.
Stop the mixer and fold in a 1/3 of the flour once you notice the flour is partly incorporated into the meringue repeat with the remaining of the flour mix.
Spoon the batter into the pan evenly and gently bang it once over the counter.
Baker for 45-50 minutes or until a wooden skewer comes out clean from the center of the cake.
Remove the cake from the oven and turn it upside down (see above notes), allow it to cool completely before removing from the pan.
Shortly before serving (about 30-60 minutes) place the egg whites and sugar in a bowl of a standing mixer. Use a hand whisk to whisk together.
Place the bowl on top of a pot of simmering water (make sure the water does not touch the bowl) and let cook while constantly whisking.
Keep cooking and whisking until the sugar has dissolved and the mixture is too hot for the touch of your finger.
Remove from the stove and let mix using the whisk attachment on medium-high until the mixture has cooled and it is light and fluffy. Add the vanilla and salt whip to mix in.
Frost the sides, tops and inside of the cake and use a kitchen torch to torch the frosting. (or in the oven, broiler setting. Check the cake every 2 minutes)