Pre-heat oven to 350F (180C). Grease and flour a 9 inch (23 cm) bundt pan or 8 inch (20 cm) cake pan.
In a medium bowl whisk together the flour, baking powder and salt.
In a medium bowl beat until stiff peaks appear the 3 egg whites.
In a large bowl beat the 4 yolks and sugar until light and creamy (about 3-5 minutes). Then add the vegetable oil, limoncello and zest, beat until smooth.
Stir the flour mixture into the yolk mixture and combine, then gently fold in the egg whites until combined. Spoon into the prepared cake pan. Bake for approximately 25-30 minutes or until toothpick comes out clean. Let cool before dusting with powdered sugar. Enjoy!
Notes
To make homemade cake/pastry flour - for every cup of all purpose flour, remove two tablespoons and replace with two tablespoons of corn starch. Be sure to sift the flour and cornstarch together a couple of times, this way it is sure to be properly combined and lump free.If you want to fancy the cake up you could glaze it with a simple Lemon glaze. Combine some powdered sugar with a little lemon juice or limoncello and mix until smooth and desired thickness. Drizzle over the completely cooled cake. Start with a cup of sifted powdered sugar and 1-2 teaspoons of limoncello or lemon juice.The cake should be stored in an airtight container or a covered cake dish. It will keep at room temperature for approximately 2 days, or keep it in the fridge for up to 5-6 days. Bring to room temperature before serving.The cake can also be frozen. Wrap the cooled cake tightly in plastic and place in a freezer safe bag or container. It will keep for up to three months in the freezer.