Heat oven to 375�. In large bowl, combine sugar, brown sugar and margarine; beat until light and fluffy. Add peanut butter, vanilla and egg; blend well. Lightly spoon flour into measuring cup; level off. Add flour, baking soda and salt; mix well. Shape dough into 3 cm balls. Place 5 cm apart on ungreased cookie sheets. With fork dipped in sugar, flatten balls in crisscross pattern. Bake at 375� for 6 to 9 minutes or until golden brown and set. Immediately remove from cookie sheets. Yield 4 dozen cookies.
Variations: Chocolate Peanut Butter Crunch Bars: Prepare dough as directed. (Omit 4 t. sugar). Stir half cup crisp rice cereal into dough. Press in ungreased 15 x 25 cm baking pan. Bake at 350� for dozen to 17 minutes or until golden brown. Cool 15 minutes. Meanwhile, melt 1 cup semi-sweet chocolate chips and half cup peanut butter in medium saucepan over low heat. Stir in 1.5 cups crisp rice cereal. Spoon mixture evenly over slightly cooled bars; gently spread. Cool completely. Cut in bars. 48 bars.
Giant Peanut Butter Candy Cookies: Prepare dough as directed. Stir in 1 cup candy-coated chocolate pieces. Using quarter cup dough per cookie, place cookies 10 cm apart on ungreased cookie sheets. Flatten to 10 cm diameter. (Omit 4 t. sugar.) Bake at 350� for 8 to dozen minutes or until golden brown. Cool 1 minute; remove from cookie sheets. 14 cookies.
Oatmeal Peanut Butter Cookies: Prepare dough as directed, decreasing flour to 0.75 cup and adding 0.75 cup rolled oats. Cover dough with plastic wrap; refrigerate 2 hours for easier handling. Shape and flatten balls as directed. Bake at 375� for 6 to 10 minutes or until golden brown. 4 dozen cookies.
Peanut Butter and Jelly Thumbprints: Prepare dough and shape into balls as directed. Increase 4 t. sugar to quarter cup; roll balls in sugar. Place 3 cm apart on ungreased cookie sheets. With thumb, make deep imprint in center of each cookie. Bake as directed. Cool completely. Spoon half t. jelly, jam or preserves into imprint in each cookie. 4 dozen cookies.