Using a stand-up mixer or electric hand-held, beat the butter well until light in color and fluffy. Add the sugar and again beat well for at least 5 minutes. I use a stand up mixer and beat the mixture 10-15 minutes. I don’t like a “grainy” cake.
One at a time add the eggs and beat only until the yellow disappears.
Stir juice, milk, zest and vanilla together.
Now mixing by hand, gradually flour to the butter-egg mixture alternating with the key lime juice and milk mixture. Begin and end with flour. Mix well but just enough to incorporate all ingredients. You don’t want a tough pound cake!
Pour evenly into the tube pan and tap pan on the counter to loosen any air bubbles.
Bake for 1 hour and 45 minutes or until cake tester comes out clean.
Cool on a cooling rack for 20-25 minutes in the pan then transfer from pan to cooling rack and allow to cool another hour or until completely cool.
The cake is far better the following day or 2 days later.
Key Lime Cream Cheese Icing
