Chocolate Fudge Shortbread

I've never made shortbread before but decided that if I was going to make it, it definitely had to involve chocolate... but this recipe went one step further and made it a chocolate fudge layer.  The hardest part of this recipe?  Spreading the shortbread dough into the pan.  There is not a large amount of dough to cover the base of a 13x9 pan and it actually took me longer to do than the shortbread took to bake.  The second hardest part?  Not eating more than a bite to make sure it tasted good enough to take to one of my bestest's holiday party tonight along with Caramel Popcorn and an oatmeal version of my Chocolate Chip Cookie Bars.  I will definitely be making these again!

1 c butter, softened
1/2 c confectioner's sugar
1/4 tsp salt
1 1/4 c all purpose flour
1 14oz can sweetened condensed milk
2 c semi sweet chocolate chips
1 tsp vanilla extract
1/4 c finely chopped nuts (I always use the Nut Topping nuts when a recipe calls for nuts)

Preheat oven to 350 F.  In a mixing bowl, cream butter, sugar, and salt until fluffy.  Gradually beat in flour.  Spread into greased 13x9x2 pan and bake for 16-20 minutes or until edges start to brown.

In a microwave safe bowl, combine sweetened condensed milk and chocolate chips.  Microwave uncovered for 1-2 minutes or until chips are melted.  Be sure not to heat too long.  Stir until smooth.  Stir in extract.  Spread over cooled shortbread.  Sprinkle with nuts and gently press into chocolate.  Refrigerate until set and cut into squares.