pumpkin pie cake

I first tried this pumpkin pie cake when one of the third grade teachers brought it to our teacher's lounge.  (Teachers LOVE food!)  It's an updated version of your traditional pumpkin pie and I must say it's terrific and always a hit.  I have been asked for this recipe many times if you need convincing.
I made this pumpkin pie cake for my husband's birthday when we first started dating.  We'd been dating for about two months and I took this to him to break him of his incessant studying.  It worked.  He set his books aside and enjoyed a square or two and still tells me to this day that I haven't made it as good as I made it that first time.  I don't believe him.
P.S.  Look at this beautiful buck sitting in the sun in our backyard.  He sat there yesterday for hours and hours and didn't mind one bit when my husband stepped outside and aimed a camera at him.  I think he likes us.  I know he thinks our yard is delicious.

pumpkin pie cake (Roxanne Le Blanc)
1 large can pumpkin puree
1 can sweetened condensed milk
3 eggs
1 cup sugar
1/2 teaspoon  nutmeg
1/4 teaspoon salt
1 1/2 teaspoons cinnamon
1 yellow cake mix, dry

Mix the pumpkin, milk, eggs, sugar and spices.  Pour into a 13x9x2 pan.  Pour dry cake mix over the top, spreading evenly.

topping
1 cup chopped walnuts, optional
1 1/2 sticks melted butter

Drizzle topping as evenly as possible over top of dry cake mix.  Bake at 350 degrees for approximately 50 minutes or until top is golden brown.  Refrigerate until cold.  Cut into squares and serve with whipped cream.