Have all ingredients at room temperature. Position oven rack to lower third of oven and preheat to 325. Grease & flour Bundt or tube pan.
Sift dry ingredients and set aside.
Cream butter and cream cheese at medium speed.
Gradually add sugar, beating until light and fluffy, about 5 minutes, stopping and scraping bowl occasionally.
Add eggs, one at a time, beating well after each addition.
Beat in vanilla and key lime juice.
Reduce speed; fold in dry ingredients in 3 additions, blending well after each addition just until smooth.
Fold in lime zest.
Spoon batter into prepared pan. Bake 60 - 90 minutes.
Cool cake upright in pan about 10 minutes before removing from pan.
Glaze: In a small bowl, whisk 1/4 c. key lime juice and 3/4 c. sugar, until well blended. Brush or spoon over cake. After glaze has set, about 10 minutes, lightly sprinkle with confectioners sugar