Preheat your oven to 350°F (177°C) and line several baking sheets with parchment paper.
In an electric stand mixer fitted with the paddle attachment, mix your brown sugar, olive oil, granulated sugar and butter on medium for 2 minutes, or until smooth and fully incorporated. With the mixer on low, add in the eggs, one at a time, blending the first completely before adding in the second. Then add the vanilla and continue mixing until everything is well blended. Take the bowl out of the mixer and set aside.
In a medium bowl, whisk together the all-purpose flour, bread flour, baking powder, espresso, baking soda and sea salt. Add this to the wet ingredients and fold until the cookie dough is almost blended. You still want to see streaks of flour. Add the chocolate chunks and mix until evenly distributed throughout. Gently roll into 3-tablespoon-sized (42-g) balls, place on the prepared baking sheet and allow about 31⁄2 inches (9 cm) of space between the dough balls to allow for spread. Sprinkle each with a pinch of sea salt flakes, if using.
Bake one sheet at a time in the center of the oven for about 11 to 12 minutes. They will look slightly underdone. Allow the cookies to cool on the baking sheet for 10 minutes, and then move to a rack to finish cooling.