Pumpkin Pie Squares

1 13oz can of evaperated milk
3 eggs
2 tsp pumpkin pie spice
½ tsp salt
1 cup sugar
1 large can pumpkin
--MIX TOGETHER—
1 pkg yellow cake mix
¾ cup butter (I just cut up a cube, and spread the butter pats around
opt.2 bags chopped walnuts
Bake 350 for 1hour