• Preheat oven to 350˚. Line 2 baking sheets with parchment paper.
Set aside.
• In a large bowl and using an electric mixer at medium-high speed,
cream 1/2 cup butter, peanut butter, sugar, and brown sugar until
light and fluffy, about 6 minutes. Add egg and vanilla, and mix at
medium speed until well combined.
• In a medium bowl, sift together flour and baking soda. Gradually
add flour mixture to butter mixture, and beat until just combined.
Gently fold in the chocolate pieces.
• Shape dough into 1 1/2- to 2-inch balls. Place dough on prepared
baking sheets, spacing 3 inches apart. Bake for 18 to 20 minutes,
or until edges are lightly brown. Cool on a wire rack.
• Line a large, flat surface with parchment paper.
• In a small bowl, combine chocolate chunks and remaining 4 tablespoons
butter.
• In a small saucepan over medium heat, bring cream to a boil.
Immediately pour hot cream over chocolate and butter. Gently
whisk until mixture is smooth.
• Dip cooled cookies halfway into melted chocolate. Gently shake off
excess, and place on the parchment-lined surface. Let chocolate
cool before serving.

 
*For testing purposes, we used Reese’s Premier Baking Pieces.