Preheat your oven to 350 degrees F. Prep a 8x8 or 9x9 pan lining with parchment paper, using clips to clip down the sides, and spraying with cooking spray. Set aside.
In a large size bowl, whisk together the melted butter and brown sugar for about 30 seconds.
Add the whole egg, and the egg yolk. This part is important. It gets the shine on the top of blondie. Whisk the eggs vigorously for about 90 seconds. It will start to lighten in color.
Whisk in the vanilla bean paste or extract.
Switch to a rubber spatula, and fold in the flour, baking soda, salt and the chocolate chips. Don’t over mix. Mix until there are no more flour streaks.
Pour the dough into the prepped pan, and all the spoonfuls of Nutella and the melted peanut butter. Drop the peanut butter and Nutella on top and use a butter knife or a toothpick to make big swirls. Do not over-swirl–you want big stripes of peanut butter and Nutella. Add the extra chocolate chips.
Bake for 25-30 minutes. The top will start to brown, and the edges will puff up a little, that’s when the blondies are done. Let them slightly cool or completely cool, cut and serve.