In a medium non-stick saucepan, combine milk and sugar. Bring mixture to a boil over medium heat; reduce heat to medium-low, stirring constantly 2 to 3 minutes.

Remove from heat and stir in peanut butter and remaining ingredients.

Transfer mixture to a lightly greased 20 x 20 x 5 cm cake tin.

Let stand at room temperature for 1 hour.

Refrigerate until ready to serve. Cut into 6cm squares.