Slightly adapted from this recipe on Taste of Home. Serves 12-16.
1 cup (two sticks) butter, softened
2-1/2 cups granulated sugar
4 large eggs
3 cups all-purpose unbleached flour
1/4 tsp baking soda
1 cup buttermilk
1 tsp pure vanilla extract
Zest of 1 navel orange (approximately 1 heaping Tbsp)
1-1/2 cups confectioners sugar
Juice of 1 navel orange (approximately 3 Tbsp)
Preheat oven to 325°F.
In the workbowl of a Kitchenaid-type stand mixer, cream the butter and sugar together until light and fluffy. Add the eggs, one at a time, and beat until well incorporated.
In a mixing bowl, combine the flour and baking soda. Add this, alternating with the buttermilk, to the mixer. When the batter is smooth, stir in the vanilla extract and orange zest.
Spray the inside of a 10- or 12-cup Bundt pan with cooking spray. Pour in the batter, making sure to distribute it evenly. Set the pan on a baking sheet.
Bake at 325F for 70 minutes, or until a toothpick inserted in the center comes out clean.
Cool the cake in the pan for 15-20 minutes, then unmold onto a wire rack to cool completely.
When the cake is cool (this will take 1-2 hours), place it on a serving plate. Whisk together the confectioners sugar and orange juice in a glass measuring cup. Add more orange juice, a few drops at a time, if needed to make the icing pourable. When the icing is smooth, drizzle all of it over the cake.
Can be made a few hours ahead. If you wish to make the cake ahead and freeze it, do not add the glaze until just before you're ready to serve.