In small mixer bowl, beat together 1/2 c peanut butter, butter, corn syrup and vanilla. Stir in icing sugar until well blended.

Melt chocolate chips in measuring cup in the microwave or in a small pot on the stove and stir in 1/4 c peanut butter. Gently stir this mixture slightly back into the peanut butter for a marble effect.

Pour into a small pie plate or pan and refrigerate until set. Keep in refrigerator. Cut into squares.

Peanut Butter Trivia * Canadians eat a total of 80, 849 kg of peanut butter a day (about 177, 868 pounds or almost 89 tons) * Smooth peanut butter outsells crunchy by 3 to 1 * Children and men prefer smooth peanut butter; women prefer crunchy * Most peanut butter is eaten at breakfast * One acre of land grows enough peanuts to make 30, 000 peanut butter sandwiches