Brown the butter in a small saucepan until bubbly and dark golden. Stir it continuously, careful to not burn it.

Remove from heat and allow the butter to cool completely to room temperature.

In a separate bowl, combine the dry ingredients (flour, baking soda, baking powder, salt).

Once the butter has cooled completely but is still liquid, add it to a large bowl with the brown butter, sugar, vanilla extract, and sourdough starter. Combine with a whisk or hand mixer until even.

Fold the combined dry ingredients into the wet ingredients. Stir until well combined.

Add chocolate chunks, chocolate chips, graham crackers, and marshmallows.

Place the dough in the fridge for at least 2 hours or refrigerate overnight, covered.

Line a cookie sheet with parchment paper. Scoop about 2 tablespoons of your chilled cookie dough and shape into balls.

Preheat the oven to 375° and place the cookie dough balls about two to three inches apart on the lined cookie sheet.

Bake for 12-15 minutes. Remove from the oven. Your cookies may be puffy and some marshmallow may ooze out the sides, but it’s fine, do not panic, proceed to the next step.

While the cookies are still hot, lift the parchment paper off the pan about a foot above the pan and drop it onto the pan. This will flatten the cookies to the perfect texture. Use a butter knife to fix the shape of the cookies to be more circular if needed.

Let them sit on the cookie sheet until they are completely cool.