Grand Marnier Cake (Orange Liqueur Cake)

I am so proud of this recipe because my daughter, Danielle, and I came up with it one day in a moment of inspiration! I used my Homemade Grand Marnier but any orange flavored liqueur will do. This cake is very light so we chose to do a orange liqueur infused whipped cream topping for it which just adds to the airiness of the cake. I think this will make a nice Christmas cake because of the wintery oranges and snowy whipped cream!
Ingredients
Cake
2 1/4 cups all purpose flour
2 teaspoons baking powder
1/4 teaspoon baking soda
1/2 teaspoon salt
4 large egg whites
1 tablespoon orange zest
2 tablespoons Grand Marnier Liqueur (plus a small amount set aside with a pastry brush for later use)
The juice of 2 oranges
1/2 cup butter room temp
1 1/2 cups sugar
Whipped Cream Topping
1 1/2 cups heavy cream
1/4 cup plus 2 tablespoons powdered sugar
2 teaspoons Grand Marnier
Mix ingredients on high with a whisk attachment until cream is stiff and holds peaks.
Tools
1 sheet cake pan OR 1 bundt cake pan. I coat the pan well with PAM spray.
Directions
First beat egg whites in a very clean bowl (no residue of fat in the bowl at all) at high speed until stiff but not dry peaks form. Set aside.
Mix the dry ingredients and set aside.
Mix 2 tablespoons of liqueur, the juice of the 2 oranges, and enough water to make 1 cup total of liquid and set aside.
Now cream the butter and sugar at high speed until creamy and light. Add the zest and mix. Add the dry ingredients and the juice mixture (no egg whites yet!) alternately starting and ending with the dry. But do not over mix, just enough to mix together.
Gently fold in the egg whites.
Pour into the pan and bake at 350 for 25-30 minutes.
Remove from oven and test by inserting a toothpick in the center, if it comes out dry it is done. It should be slightly golden on top.
Cool on counter for 10 minutes.
Remove from pan to a rack and cool completely. Or you can leave the sheet cake in the pan and serve from there. If using a bundt pan cool for 10 minutes and then remove and place on a rack to cool completely.
Half way between the cooling process brush a light coat of Grand Marnier all over the top of the cake. If it is still slightly warm it will soak this up.
To Serve
Cut into squares and serve each piece with a big dollop of cream.