Whisk butter and sugars: In a large bowl, whisk together the melted butter, brown sugar, and granulated sugar until smooth and combined.

Add wet ingredients: Add the eggs, egg yolk, milk, and vanilla extract. Whisk until fully incorporated.

Mix in dry ingredients: Add the flour, cornstarch, baking soda, baking powder, and salt. Stir just until combined.

Add chocolate chips: Fold in the mini chocolate chips.

Roll: Transfer the dough onto a large sheet of parchment paper. Place another sheet of parchment on top and roll the dough with a rolling pin into a rectangle about 1/4-inch thick. (You could also just use clean hands to press it out into a slab, but I find this is a little easier)

Chill: Transfer the dough slab (still between the parchment sheets) to a baking sheet or cutting board. Freeze for at least 1 hour, or until firm. Start Timer

Cut into fries: Preheat the oven to 350°F. Remove the dough from the freezer and peel away the top layer of parchment. Using a sharp knife or pizza cutter, cut the dough into fry-shaped strips. Aim for narrow, uniform pieces (use a ruler if needed) so they bake evenly. You should get about 30-35 cookie fries.

Bake: Arrange the cookie fries on silicone-lined baking sheets, leaving a little space between each piece. (A silicone baking mat works best for maintaining their shape.) Keep the other cookie fries in the freezer between batches so the dough stays cold. Bake for 8-9 minutes. Start Timer

Shape fries: Remove from the oven and immediately use an offset spatula, bench scraper, or butter knife to gently nudge any spreading edges back into straight fry shapes.

Finish baking: Return to the oven and bake for 1-2 more minutes Start Timer, or until the edges are lightly set but the centers still look slightly underdone. Slightly underbaking is key.

Cool and finish: Allow the cookie fries to cool on the baking sheet for 10 minutes before carefully transferring to a wire rack. Start Timer Sprinkle with Maldon flaky sea salt while still slightly warm.

Serve: Serve with your favorite dipping sauces and enjoy!