Poppyseed angel food cake recipe with grapefruit curd

Ingredients

• 1 cup cake flour
• 1 1/2 cups superfine sugar
• 12 large egg whites are room temperature
• 2 table spoons lukewarm water
• 1 1/4 tea spoons cream of tartar
• 1/2 tea spoon salt
• 2 tea spoons vanilla
• 3 table spoons poppyseeds
• 1 batch of grapefruit curd
• 12 large egg yolks
• 1 cup superfine sugar
• 2 tea spoons grapefruit zest
• 3/4 cup fresh squeezed grapefruit juice
• 3 table spoons fresh squeezed lemon juice
• 1 cup cold, unsalted butter cut into chunks.