Preheat oven to 375°F (190°C).

In a large bowl, combine flour, brown sugar, baking powder, and salt.

Cut butter into 1/2-inch cubes and add to the flour mixture.

Use a pastry blender or two knives to cut the butter into the flour until it resembles coarse crumbs.

In a small bowl, stir together peanut butter, milk, eggs, and vanilla extract.

Add the peanut butter mixture to the flour mixture and knead until just combined.

Knead in chopped peanuts.

Pat the dough out to a 1/2-inch thickness on a cutting board.

Cut out 16 rounds using a floured 2 1/2-inch to 3-inch crinkled round biscuit cutter.

Place 8 rounds on an ungreased baking sheet.

Top each round with a piece of chocolate and one of the remaining circles of dough.

Gently press the edges to seal.

Bake for 17-19 minutes, or until lightly browned.

Transfer the baking sheet to a wire rack and cool for 5 minutes.

Use a spatula to transfer the scones to the wire rack to cool completely.