Poppy Seed Cake

Ingredients for cake:

• 1/3 cup (80 ml) dry poppy seeds
• ¾ cup (180 ml) milk
• ¾ cup (175 g) butter, at room temp
• 1½ cups (360 ml) sugar
• 2 cups (480 ml) flour
• 1½ teaspoons vanilla extract
• 2½ teaspoons baking powder
• ¼ teaspoon salt
• 4 stiffly beaten egg whites (4 if eggs are large, else 5; keep yolks for filling); Frank adds ¼-½ teaspoon of Cream of Tartar to the unbeaten egg whites, to help stiffening and stabilizing [Cream of Tartar or potassium bitartrate, also potassium hydrogen tartrate, is a component of baking powder: baking powder comprises baking soda and cream of tartar]

Ingredients for cream filling: