1. Combine flour, sugar, soda, 1/2 C.butter, salt and vanilla and press into a greased 9 x 13 pan. Bake at 325° for 10-12 minutes, until light brown. Remove from oven, spread marshmallows over the crust. Return to the oven for 1-2 minutes until marshmallows are puffed.
2. Melt corn syrup, 1/2 C. butter and peanut butter chips.
3. Add peanuts, heat until mixture is spreadable and pour over marshmallows. Cool before cutting bars.