Place the butter in a medium sized saucepan and melt over medium heat. Once melted, keep cooking while stirring occasionally and the butter begins to sizzle and foam. It will then start to turn an amber brown color and start to give off a nutty aroma. Once browned, remove from the stove and pour the butter into a large mixing bowl.
In the same saucepan, no need to clean it, it should still have a little butter in it, add the graham cracker crumbs. Toast the crumbs over medium heat for about 5 minutes or until lightly browned. Remove from the heat and pour into a bowl to cool.
In a medium sized mixing bowl, whisk together the flour, oats, baking soda, and salt. Set aside.
To the bowl with the cooled brown butter, add the granulated and brown sugars and whisk until combined. Whisk in the honey, it may look a little split after this but don't worry. Add the espresso powder and vanilla and whisk, followed by the eggs. Once you whisk in the eggs the mixture should even out. Pour the dry ingredients into the wet ingredients and, using a large spatula, fold the two together until mostly combined. Finally, add in the cooled graham cracker crumbs and fold them in. The dough should be a little thin and sticky.
Cover the bowl with cling wrap and place the dough in the fridge to chill for 30 minutes.
Preheat the oven to 350℉, line two baking sheets with parchment paper or a silicon baking mat. Set aside.
Once chilled, scoop the dough into balls and place on the baking sheets, roughly two inches apart. Bake the cookies for 12-13 minutes or until browned on the bottom and sides but still a little gooey in the middle. Let the cookies cool on the baking sheet fro 10 minutes before enjoying warm or transferring to a wire cooling rack to cool completely. Cookies stay fresh stored in an airtight container for up to 5 days.
