Melt the butter in a saucepan over a medium heat.

Stir in the brown sugar and milk and bring to a boil.

Cook for two minutes, stirring frequently.

Remove from heat and add the "Panda" peanut butter and the vanilla.

Transfer to a large mixing bowl and beat in the icing sugar until smooth.

Pour into a square baking dish and chill until firm.

Cut into squares to serve.

Makes 16 squares.