Beat egg yolks until well combined and thick. Add in 3/4 cups sugar, lightly beat. Add in juices and blend together. Combine and beat flour, baking powder and salt until well combined.
In another bowl, beat egg whites until foamy and thick. Beat sugar until stiffer peaks form. Don't over beat. Fold eggs whites into yolk mixture with a spatula. Combine gently but be thorough. In a jelly roll pan, grease and line with parchment paper. Grease and flour paper. Pour the batter into the pan. Bake at 325F for 25 to 30 minutes or until golden.
Let the cake cool for 5 minutes in the pan. While it's cooling, dust a clean kitchen towel with confectioners' sugar.
Invert the cake onto the towel, carefully remove parchment paper and roll the cake up in the towel. Allow to cool completely.
For the Lemon Curd:
In a pan, the strain egg yolks and beat lightly with a wire whisk. Beat in sugar until blended. Stir in lemon juice gradually. Heat on low, while stirring constantly with a wire whisk until mixture coats back of wooden spoon or 168F on a candy thermometer. Do not boil the mixture.
Turn off the heat, whisk until cooled. Add cold, cubed butter and whisk in bits to yolk mixture until melted. Let cool completely.
For the Whipped Cream:
Using a metal bowl and metal spatula, add cream and sugar. Whisk on high until it reaches stiff peaks.
For the Assembly:
Unroll the cake. Once cooled, spoon a flat layer of lemon curd onto cake.
Carefully roll and transfer to a plate.
Using a large closed star tip, pipe whipped cream rosettes on the top.
Notes
Notes: Curd filling can be stored and kept in the refrigerator for later use.