Preheat oven to 450 degrees.  Line your pie plate with the pie crust.  Combine the 3 tablespoons of butter and 1/3 cup brown sugar, beat until smooth. Stir in pecans.  Carefully pat into the bottom of the pie shell, bake at 450 degrees for 8 minutes.  Remove from the oven and let stand for 10 minutes.  Combine the eggs, pumpkin puree, sugars, pumpkin pie spice and salt and beat until well combined.  Slowly add the evaporated milk.  Mix until milk is well incorporated. Pour into prepared crust.  Reduce heat to 350 degrees.  Bake pie for 50 minutes or until a knife comes out clean.  Cool.  Serve with whipped cream.