1. Preheat oven to 350 degrees.
2. In a large mixing bowl, beat together butter, vegetable oil, sugar, eggs and vanilla.
3. In a separate mixing bowl, blend the flour, salt and baking soda.
4. Make a well in the middle of dry ingredients and add egg and butter mixture to blend.
5. Drop by spoonfuls onto greased cookie sheet and bake for 6-8 minutes or until edges turn golden brown.