Make the cake: In a large mixing bowl, combine butter and cream cheese until light and fluffy. Mix in sugar, then gradually add in eggs 1 to 2 at a time, beating on low until combined.
Mix in lime juice, then flour. Fold in lime zest.
Grease 4 mini loaf pans and pour in cake batter until each one is about 3/4 full. Bake until a toothpick inserted in the center comes out mostly clean, 43 to 45 minutes. (If you don’t have mini loaf pans, you can grease and fill a bundt pan and bake 70 to 73 minutes.) Let cool for 15 minutes.
Make the glaze: Whisk together powdered sugar, lime juice, water and vanilla. (If the glaze is too thick, add extra water, about a teaspoon at a time.) Pour on top of cooled pound cake, then top with lime zest and serve.