Not quite so common is the Orange pound cake. A nice citrus flavored cake.
Preheat oven to 350 degrees F.
Lightly coat baking dish with butter.
In a medium sized mixing bowl, sift together flour, salt, baking powder and baking soda and set aside.
With a vegetable peeler, remove the peel from the orange and coarsely chop the peel.
Cut the orange in half and squeeze 1/2 cup juice.
Place the sugar and peel into a food processor, pulsing until peel is finely chopped.
Combine buttermilk, 1/4 cup orange juice and vanilla in a small glass measuring cup.
(Reserve remaining juice for caramel sauce).
Combine the butter and the orange-sugar mixture in large mixing bowl on medium-high speed until combined.
Beat in the egg and egg whites, one at a time, beating well after you add each one.
At low speed, add flour mixture alternately with buttermilk mixture, beginning and ending with dry ingredients.
Spoon batter into prepared pan.
Arrange orange slices on top of cake, press in slightly.
Bake 35 to 40 minutes or until a toothpick inserted in center comes out clean.
Cool on a rack.
Orange Caramel Sauce
Combine water and sugar in small saucepan and stir with a wooden spoon until sugar is moistened.
Bring to simmer over medium-low heat; cover and simmer 2 to 3 minutes until sugar dissolves.
Uncover and cook until sugar turns amber, 5 to 6 minutes.
Remove from heat and slowly stir in reserved orange juice (mixture will bubble vigorously).
Return to heat and cook, stirring, until sugar dissolves.
Cool sauce and serve with the cake.
Ice cream also goes well with this cake.