Preheat oven to 350°F. Grease and flour 9x13 cake pan. Bring to boil first three ingredients. Pour over flour and sugar. Mix well and add other ingredients except for marshmallows and mix well. Fold in marshmallows. Pour into cake pan.
Bake for 30-35 minutes.
Bring to boil first 3 ingredients. Add powdered sugar. Stir in nuts and pour over cake as soon as it comes out of oven.