White Chocolate Blondie

This is a clone recipe of Applebee's White Chocolate and Walnut Blondie, although I think they may have changed the name. It calls for walnuts, but I prefer pecans. The sauce is amazing! I always double it so that there's plenty to go around.

Ingredients:

CAKE:
4 egg whites
½ cup butter softened
½ cup light brown sugar - (packed)
¼ cup granulated sugar
1 teaspoon vanilla extract
2 ¼ cups all-purpose flour
1 teaspoon baking soda
½ teaspoon baking powder
¼ teaspoon salt
½ cup milk
8 ounces white chocolate cut into chunks
½ cup chopped walnuts or pecans

SAUCE:
½ cup butter softened
½ cup powdered sugar
2 oz cream cheese softened
2 tablespoons maple syrup
¼ teaspoon salt
SERVING:
vanilla ice cream
½ cup chopped walnuts or pecans

Preheat oven to 325 degrees.
To make the blondie cake, whip the egg whites until they are stiff and form peaks. Add softened butter, ½ cup packed brown sugar, ¼ cup granulated sugar, and vanilla and mix with an electric mixer until smooth.
In a separate bowl sift together flour, baking soda, baking powder and ¼ teaspoon salt. Add the dry ingredients to the wet ingredients and mix well until smooth. Mix in milk, white chocolate chunks, and walnuts.
Pour ingredients into a greased 9— by 13-inch baking pan and bake for 40 to 45 minutes (mine seems to get done after about 30 minutes, so watch closely!) or until cake is golden brown on top.
While cake bakes, combine all ingredients for the sauce in a medium bowl with an electric mixer. The sauce will be fluffy at this point.
Arrange the cake on the skillet or plate. Heat up the sauce for 30 to 60 seconds in the microwave until hot and pourable. Place a scoop of vanilla ice cream on the cake, then drizzle some of the sauce over the top, followed by a tablespoon of chopped walnuts. Serve immediately.