Pre heat oven to 350 degrees. Butter and flour a 9" spring form pan
In the bowl of a stand mixer, combine the egg yolks and 3/4 cup sugar. Beat on high for about 4 minutes until mixture is thick and pale yellow. Add in 1/2 tsp vanilla paste and lemon paste or extract. Scrape into a large bowl. Cover and set aside. Wash the bowl and whisk off the stand mixer.
Beat the egg whites, salt until they form stiff peaks. Add in remaining 2 TBSP of sugar and beat about 20-25 seconds more.
Fold one third of the egg white mixture Ito the egg yolks and sugar. Sift over one third of the flour. Repeat taking care not to deflate the egg whites until all the ingredients are well combined. Gently fold in the melted butter. Pour the batter into the spring from pan and bake for 25 minutes until the top is golden brown and a cake tester comes out clean. Let the pan cool for 5 minutes, then release from the pan. Once the cake is cooled, cut into 2" cubes. Place one layer of the cubes into the trifle dish. Finish assembling in directions below.