Preheat oven to 350*F. Lightly grease a 15x10" jelly roll pan with butter or vegetable oil.
To make cake:.
Sift the flour, baking soda, and salt together in a small bowl and set aside.
Using electric mixer on medium high speed, cream the butter, cream cheese, sugar, vanilla, and orange zest together in a medium mixing bowl until light and fluffy, about 2 minutes. Stop the mixer once or twice to scrape the bowl with a rubber spatula.
Add the eggs one at a time and beat on medium low speed until each yolk is partially blended, 10 seconds. Scrape the bowl after each addition.
Now fold in half the dry ingredients with the spatula until partially incorporated, then turn the mixer to low and blend for a few seconds. Repeat with the remaining dry ingredients, blending 10 seconds with the mixer. Finish the mixing by hand with a few broad strokes of the spatula. Spread the batter evenly in the prepared pan.
Bake until the cake is lightly golden, springs back to the touch, and a toothpick inserted in the middle comes out clean, 20 to 25 minutes. Allow the cake to cool completely on a rack while preparing the glaze.
Place all the ingredients for the glaze in a small bowl and stir heartily with a whisk until blended.
Pour the glaze over the cake and spread it evenly with a frosting spatula. Allow the glaze to harden 3 to 4 hours before serving. Enjoy!