In a mixing bowl, combine peanut butter, melted butter, powdered sugar, and vanilla extract until smooth and thick.
Line an 8x8 inch pan with parchment paper and press the peanut butter mixture evenly into the pan.
Chill the peanut butter base in the refrigerator for 20 minutes.
Melt chocolate chips with coconut oil in a microwave-safe bowl in 30-second intervals, stirring until glossy and smooth.
Pour the melted chocolate over the chilled peanut butter layer and spread it evenly.
Sprinkle chopped roasted peanuts evenly over the chocolate layer and gently press them in.
Refrigerate the assembled squares for 40 minutes until firm.
Lift the set squares out using the parchment paper and cut into 16 pieces to serve.