Preheat oven to 300 degrees.
In a double boiler, melt the semisweet chips over hot, not simmering wter.
Set aside to cool to room temperature.
In a small bowl, whick together the flour, baking soda, and salt.
In a medium bowl, whisk together the brown and granulated sugars, then add the butter and beat until combined. Add the peanut butter and beat until smooth. Add the eggs and vanilla, and beat just until combined. Add the flour mixture and the milk chocolate chips, and beat until nostreaks of flour are visible.
Pour in the melted chocolate and miz partially with a wooden spoon until marbled.
Drop the dough in 3 Tblsp mounds, 2 inches apart on an ungreased baking sheet.
top with one whole peanut.
Bake for 23 minutes or until just set but still soft.
Cool on the cookie sheet for 30 seconds, then transfer to a wire rack to cool completely.