Place egg whites in a huge bowl. Filter 1/2 cup sugar and flour together two times; put away.
Add cream of tartar, vanilla and salt to egg whites; beat on medium speed until frothy. Bit by bit beat in excess sugar, 2 tablespoons all at once, on high until solid lustrous pinnacles structure and sugar is broken down. Continuously overlap in flour blend, around 1/2 cup at a time.
Tenderly spoon player into an ungreased 10-in. tube container. Slice through hitter with a blade to eliminate air pockets. Heat on most minimal broiler rack at 350° until brilliant brown and whole top seems dry, 35-40 minutes. Promptly upset dish; cool totally, around 60 minutes.
Run a blade around side and focus container of dish. Eliminate cake; split into two flat layers. Put cake base on a material paper-lined baking sheet. Spread with lemon curd; supplant cake top.
For meringue, in a little bowl, beat egg whites and cream of tartar on medium until delicate pinnacles structure. Bit by bit beat in sugar, 1 tablespoon at an at once, until solid shiny pinnacles structure and sugar is broken down. Spread up and over and sides of cake.
Heat at 350° until brilliant brown, 15-18 minutes. Move to a serving plate. Refrigerate extras.
