add peanuts to a food processor and blend until a thick nut butter forms. stream in oil and vanilla with the processor on, continuing to run it until the mixture is smooth this took me about 3-4 minutes.
you can add more oil if needed, just do it in small increments. turn off processor add melted chocolate and turn processor back on. blend until smooth.
i kept mine at room temperature for a week, but i do recommend refrigerating the butter if you want to keep it a few weeks.