In a large bowl mix together the butter, brown sugar, egg, and vanilla. Then stir in the baking powder, baking soda, salt, and flour until all of the ingredients are well-blended.
Fold in the white chocolate chips and chopped nuts.
The batter should be pretty thick. Pour it into a greased 9x9 inch pan, and cook for 20 to 25 minutes.
While the blondies are cooking, you can prepare the maple butter sauce.
Maple Butter Sauce
In a medium saucepan, combine the maple syrup and butter. Cook over low heat until the butter is melted.
Next, add the brown sugar and softened cream cheese, stirring constantly until cream cheese has melted.
After the blondies are finished cooking, cut them into squares. Top with a scoop of vanilla ice cream, drizzle maple butter sauce over the top, and sprinkle on additional chopped pecans.
Notes
Wait until the blondies cool down before you cut and serve them.