Butter tart squares

Oh these are so rich! but they were delicious! These bars have a shortbread base topped with a gooey filling speckled with raisins. Next time I'll try them with walnuts instead of raisins. This recipe comes from http://joyofbaking.com/ButterTartSquares.html

Here's the recipe as published on http://joyofbaking.com/

Butter tart Squares

Shortbread Base:
1/2 cup (113 grams) unsalted butter, chilled, and cut into 1 inch (2.54 cm) pieces
3 tablespoon (40 grams) granulated white sugar
1 cup (140 grams) all-purpose flour
1/8 teaspoon salt
Filling:
1/4 cup (57 grams) unsalted butter, softened
1 cup (215 grams) light brown sugar
2 large eggs
1/4 cup (60 ml) light corn syrup
1 teaspoon pure vanilla extract
1 tablespoon (15 grams) all purpose flour
1/8 teaspoon salt
1/2 teaspoon baking powder
2/3 cup raisins or
2/3 cup pecans or walnuts, chopped

Preheat oven to 350 degrees F (177 degrees C) and place oven rack in the center of the oven. Butter (or use a non stick cooking spray) an 8 x 8 inch (20 x 20 cm) pan.

Shortbread Base: In the bowl of your electric mixer, or with a hand mixer, cream the butter and sugar until light and fluffy. Add the flour and salt and beat until the dough just comes together. Press onto the bottom of your greased pan and bake for about 20 to 25 minutes, or until pale golden in color. Remove from oven and place on a wire rack to cool while you make the filling

Filling: In your food processor or with a hand mixer, cream the butter and sugar until light and fluffy. Beat in the eggs, one at a time, until incorporated. Then beat in the corn syrup and vanilla extract. Stir in the flour, salt, and baking powder.
Sprinkle the raisins or nuts evenly over the baked shortbread base. Then pour the filling over the raisins (and/or nuts) and bake for about 20 - 25 minutes or until the filling is set. Remove from oven and place on a wire rack to cool. Serve at room temperature or chilled.