Preheat your oven to 350F (175C) and generously grease (with shortening) and flour a 10 inch tube pan or 12 cup bundt pan.

Place your butter in a large bowl and use an electric mixer to beat the butter until it is creamy and smooth.

Scrape down the sides of the bowl and add the sugar. Beat until the ingredients are well combined and light and fluffy (about 1-2 minutes).

In a separate bowl, combine your eggs, additional egg yolks, vanilla extract, and salt. Use a fork to lightly beat the eggs and yolks until all egg yolks are broken up.

With mixer on low speed, slowly pour egg mixture into your batter, allowing it to gradually become incorporated.

Once all of the egg mixture is incorporated, pause to scrape down the sides and bottom of the bowl, then increase speed to medium-high and beat for another 1-2 minutes.

Reduce mixer speed to low and gradually add flour to the batter until all has been added.

Scrape down the sides and bottom of bowl and stir again on medium speed until well-combined and beat for another minute.

Spread batter evenly into prepared tube pan, use a spatula to smooth the surface of the batter.

Transfer to 350F (175C) oven and bake for an hour and ten to an hour and fifteen minutes or until a wooden skewer inserted in the center comes out clean.

Allow cake to cool for at least 20 minutes then run a knife around the sides of the tube pan and the center.

Carefully invert pound cake onto a cooling rack and allow to cool completely before serving.