Melt margarine in heavy sauce pan. Mix cake mix with eggs, pecans and walnuts together. Pour melted margarine over these ingredients and continue to mix together. It's best to mix by hand instead of electric mixer. Press into 9x13 inch greased pan. Set aside.
On medium speed mix above ingredients until creamy and all dissolved. Pour over mixture you have set aside in 9x13 inch pan. Bake at 350F for 35-45 minutes. Your icing will become golden brown. Remove from oven and let cool completely. Cut into squares.
Cajun Country -- New Iberia, Louisiana