Do not preheat the oven. Butter and flour a large (10-12-cup) Bundt or tube pan. You can set the pan on a foil-covered baking sheet in case of any over-flow. (If your pan is the correct size, overflow should not be an issue.)
Sift together the flour and salt on a piece of parchment paper and set aside.
Beat butter and cream cheese at medium-high speed of electric mixer until blended and creamy, about 8 minutes. Gradually add sugar, beating another 5-7 minutes on medium. The batter should get very fluffy and pale yellow, with no discernible lumps of cream cheese.
Add eggs, one at a time, mixing on low just until yellow disappears. Scrape the sides of the bowl after 3 eggs.
With mixer on low, slowly pour in the flour from the parchment paper. Beat on low speed just until blended. Be sure to scrape the sides and bottom of bowl to blend every bit. Add vanilla and stir or mix just until blended.
Pour batter into the prepared pan and place in cold oven along with a 2 cup oven-proof measuring cup or bowl filled with water.
Bake at 300° for about 1 hour and 15-30 minutes or until a cake tester inserted in center comes out with just a few moist crumbs. Start checking at about 1 hour and 15 minutes.
Let cake cool in pan on wire rack for 15 minutes then flip onto wire rack.
Notes
Ingredients
Use room temperature ingredients. I set out the butter and eggs about an hour before making the cake.
Use high quality ingredients - I only use Domino's Granulated Sugar.
Use White Lily all-purpose flour or a comparable low-protein all-purpose flour or cake flour.
Use good quality, stick butter. Do not use margarine. I only use Land O' Lakes unsalted butter.
Aerate the flour before measuring—take the measuring cup and stir it around in the canister, just to mix and loosen the flour prior to measuring.
Crack the eggs and place in a bowl before adding to the sugar mixture. This ensures you don't accidentally get a piece of shell in the batter, and also makes it easier to pour in the eggs.
Mixing the Pound Cake Batter
Pound cakes are unique in that they do not use leavening agents, other than a small amount of salt. So to make the cake rise properly, the mixing technique is important.
Be sure that you beat the butter and cream cheese until it's creamy and then add the sugar GRADUALLY and beat until the mixture is light and fluffy. This will take several minutes, but these steps are vital to the success of the cake because this is what whips air into the cake batter and makes it rise during baking.
Don't over-beat after adding the eggs. Just beat until the yellow is blended in after each egg.
Prepping the Pan and After Baking
Grease the pan well and dust with flour. The flour helps the cake batter adhere to the sides of the pan.
The cake should cool about 10 minutes in the pan and then be flipped onto a rack to cool completely.