For Cookies:
Preheat oven to 350°F. 

Combine oats, flour and baking powder in a medium bowl; set aside. Beat peanut butter, sugar and butter in a large bowl with mixer at medium speed until creamy.  Add egg, corn syrup, water and vanilla; beat until smooth.  Stir in flour mixture until well blended.

Shape dough into 60 (1-inch) balls.  Place 2 inches apart on ungreased cookie sheets.  Flatten each ball to a 2-1/2-inch circle using fingertips or heel of hand,

Bake 8 to 10 minutes or until golden around edges.  Cool 1 minute on cookie sheet.  Remove; cool on wire rack.

For Cookie Filling:
Combine peanut butter and corn syrup in a small bowl; stir until blended. Spread 1 rounded teaspoonful filling on bottoms of half the cookies; top with a second cookie.

TIPS:

Serve with a tall glass of cold milk. These are rich and delicious!

Do not soften butter for this recipe; cookie dough will be easier to shape into balls if butter is cold.

If necessary, place cookie dough in freezer for 15 minutes for easier handling.