Nancy'S Brown Sugar Nut Bars - cooking recipe

Ingredients

For the bars
1 (16 ounce) box light brown sugar
1 cup butter (2 sticks)
2 large eggs
2 cups sifted flour
1 teaspoon baking powder
1/2 teaspoon salt
1 cup coarsely chopped pecans or 1 cup walnuts
For the Icing
1 tablespoon water
1 cup powdered sugar
2 tablespoons mayonnaise (She uses Hellman's)
1 teaspoon vanilla

Preparation

Preheat oven to 350\u00b0.
Cook sugar and butter in top of double boiler over hot water until sugar dissolves.(My mother uses a 3-quart heavy pot without the double boiler).
Let Cool.
Add eggs, one at a time, beating thoroughly after each addition.
Stir in remaining ingredients.
Spread in an ungreased 15 x 10 x 1-inch jelly-roll pan.
Bake at 350\u00b0 for 25 minutes (she usually cooks 22 minutes).
While hot cut into 2-inch squares.
Cool in pan on rack.
Frost: Icing recipe below if desired--*It's also good on other bars as well*.
Mix frosting ingredients together in a small bowl until creamy. (It is supposed to be thin).