Preheat your oven to 350°F (175°C).
Line your 9x13 inch baking pan with parchment paper, leaving some overhang on the sides.
In a large mixing bowl, combine the peanut butter, sugar, eggs, sweetened condensed milk, melted chocolate, and vanilla extract. Whisk until smooth.
Fold in the coarsely chopped peanuts using a rubber spatula until evenly distributed.
Pour the batter into the prepared baking pan, spreading it out evenly.
Bake for 25-30 minutes, or until the edges are golden brown and a toothpick comes out with moist crumbs.
Cool in the pan for about 10 minutes, then lift out using the parchment and cool completely on a wire rack before slicing.