Cream together the butter, shortening, sugar and vanilla.
Sift together the flour, baking soda and salt. Add to sugar mixture and mix well, being careful not to over mix.
Drop heaping teaspoonfuls of dough on ungreased cookie sheet and flatten each with the tines of a fork (dip fork into small bowl of water so that dough doesn't stick to fork). Do this once or twice, depending on the size of cookie and fork.
Bake for 13 to 15 minutes. After each pan is removed from oven, carefully place 5 or 6 chocolate chips on top of each cookie while they are still hot. When chocolate is glossy and soft, spread with knife.
