Heat a large sauté pan over medium-high heat. Add your butter and cook until melted and browned (about 4-5 minutes).

Remove from heat and add cinnamon. Stir to combine. Then, add your brown sugar and white sugar.

Let mixture cool slightly and stir to combine. Then, add your peanut butter, which will melt as it incorporates.

Add your egg and vanilla extract and whisk until combined.

In blender or food processor, combine roasted peanuts and cornstarch. Pulse in short bursts until peanuts are finely ground. Do not over-blend.

Place a sifter over a large bowl. Add your ground peanuts, AP flour, baking soda, and salt.

Sift dry ingredients into bowl. Then, add your dry ingredients and dark chocolate, chopped into large chunks, into your cookie dough.

Fold your dry ingredients and chocolate in with a spatula. Chill dough 1-2 hours or up to overnight.

The next day, remove dough from fridge and allow to come to room temperature (1 hr).

Scoop cookie dough into 8 equal balls onto two parchment-lined baking sheets, spacing cookies at least 2-3" apart.

Preheat oven to 350°F. Press dough balls down with the bottom of a glass or cup into thick pucks. Bake for 12-14 minutes until gooey in the center and golden around the edges.

Remove from oven and let cookies chill on the baking sheet for 15-30 minutes. Sprinkle with sea salt and serve.