• In a medium bowl, whisk the flour, baking soda, salt, and espresso powder together. Set aside.
• In the bowl of a stand mixer with the paddle attachment, cream the butter, granulated sugar, and brown sugar for 5-7 minutes. Scrape the bowl as needed.
• Add the egg, egg yolk, and vanilla. Mix to combine.
• Add the dry ingredients 1/2 at a time, mixing until just combined. Leaving a few streaks of flour is fine. 
• Chop the chocolate bar, and save back a few pieces as well as a few chocolate chips to top the cookie dough with before baking.
• Chop 6 of the Oreos into roughly the same size as the chopped chocolate. 
• With a rubber spatula, fold in the chocolate chips, chopped chocolate, and chopped Oreos.
• Use a large (3 TBSP) cookie scoop to portion the dough onto a sheet pan. Chill in the fridge for 30 minutes.

To Bake As Is (without stuffing with extra Oreo

• Preheat the oven to 350 and line two cookie sheets with parchment paper.
• Roll the chilled cookie dough between your palms into a smooth ball.
• Press chocolate chips and chopped chocolate into the top and sides of the dough. Break apart 4 more Oreos into large chunks and press them into the top of the dough as well.
• Bake 5-6 cookies per sheet and give them enough room to spread.
• Bake at 350 for 10 minutes. Remove from oven and swirl a round cookie cutter around the hot cookie to shape into a perfect circle.
• Top with flaky salt and enjoy.

To Bake Stuffed with Extra Oreo

• Preheat the oven to 350 and line two cookie sheets with parchment paper.
• Grab a cookie dough ball and press it flat into your palm. Place an Oreo in the center, then fold the extra dough up and around the Oreo, sealing the Oreo inside. Shape it into a nice thick disc shape.
• Press extra chocolate chips and chunks into the top and sides of the dough.
• Break apart 4 more Oreos into large chunks and press them into the top of the dough as well.
• If the dough has warmed up, place back into the fridge for 10-15 minutes so that it is firm.
• Bake at 350 for 10 minutes, remove from oven and use a round cookie cutter to scoot the dough back into a perfectly round shape, then place the cookies bake into the 350 degree oven for an additional 2 minutes.
• Remove from oven and scoot the cookies with the round cookie cutter a final time.
• Sprinkle with flaky salt and enjoy.