Heat oven to 375 degrees F.

In a large bowl, combine 1/2 cup sugar, brown sugar and butter; beat until light and fluffy. Add peanut butter, vanilla and egg; blend well. Add flour, baking soda and salt; mix well. Shape dough into 1-inch balls. Place 2 inches apart on ungreased cookie sheets. With fork dipped in sugar, flatten balls in criss-cross pattern.

Bake at 375 degrees F. for 6 to 9 minutes or until set and golden brown. Immediately remove from cookie sheets to wire rack to cool. Makes about 4 dozen cookies.