Only changes I made were to use pecans instead of walnuts, and I added a little maple flavoring to the frosting.

I cooked them in a large glass baking pan for 40 minutes.

Frosted Maple Walnut Bars

2 cups all-purpose flour
1/2 teaspoon baking soda
1/2 cup packed light brown sugar
1/2 cup (1 stick) butter, softened
1 cup pure maple syrup, preferably Grade B
1 large egg
2 teaspoons vanilla extract
1 cup rough chopped walnuts
1 batch Maple Walnut Icing (see below)

1. Prepare a 9- or 10-inch square or round baking pan with shortening and flour. I like to line the bottom with wax paper or parchment paper to be sure it comes out cleanly. Preheat the oven to 350 degrees F.

2. In a bowl, mix the flour and baking soda together and set aside.

3. In your mixer bowl, beat the brown sugar and butter to form a paste, scrape the sides and then add the maple syrup, the egg and vanilla. Beat on medium speed until the mixture is smooth. This usually takes several minutes.

4. Add the dry ingredients all at once and stir in the nuts. Mix only until the flour is combined. Pour into the prepared baking pan and bake until the center tests done, this will take over 20 minutes.

Remember the time will change for different size pans, be sure that you write on your recipe what size pan you used and how long you baked it!! You can touch it, it will be firm and lightly golden brown, and the tip of a knife or a toothpick will come clean.

5. Cool about 10 minutes, then turn the whole thing out onto a cooling rack and then re-invert so the top is facing up. If you used a piece of wax/parchment paper, peel it off before re-inverting it.

6. Cool completely and then top with the icing.
Spread on the bars evenly and refrigerate the bars before cutting.
If you like, place a walnut piece on top of each piece, or sprinkle the top with finely chopped walnuts.
To cut evenly it's much easier if the icing is firm. I like to use one motion through the whole width of the bar.
I gently mark the lines to cut and then lay the knife against the mark and push through the whole bar.
It makes a nicer cut.
If the icing loosens before you are done, just pop back into the fridge to firm it up!

7. Store the bars in a air-tight container, in the refrigerator, if frosted. The yield depends on how large or small you cut the bar. I usually cut them 8x3-inches for 24 bars.

MAPLE WALNUT FROSTING:

1/2 cup (1 stick) butter, softened
3 ounces cream cheese, room temperature
1 Tbsp packed brown sugar
1/4 cup pure maple syrup
1 cup (maybe a little more) powdered sugar
Chopped walnuts for garnish if desired

1. In a bowl, cream the butter and cream cheese until smooth.

2. Add the brown sugar and maple syrup and beat until smooth. Beat about 2-3 minutes to help cream the brown sugar and remove any grittiness.

3. Slowly add the powdered sugar until thick. If it is a thin mixture, add a little more powdered sugar. Correct with more maple syrup if it becomes too thick.

4. Refrigerate frosting.