01 -
In a medium stainless steel sauté pan set over medium heat, melt the butter. Swirl the pan occasionally and continue to cook. The butter will become foamy with audible cracking and popping noises. Once crackling becomes quieter, continue swirling or stirring until the butter develops a nutty aroma and brown bits form at the bottom. Remove from heat when these bits turn amber in color, and pour into a mixing bowl, including all the flavorful brown bits.
02 -
Add the granulated sugar and brown sugar to the hot butter, stirring to combine. Set aside to cool to room temperature.
03 -
In a medium bowl, combine the all-purpose flour, bread flour, baking soda, baking powder, sea salt, and espresso powder.
04 -
To the cooled butter mixture, whisk in the eggs, egg yolk, and vanilla until combined.
05 -
Gradually stir the flour mixture into the wet ingredients with a rubber spatula. Fold in the chocolate chunks and toffee bits until evenly distributed.
06 -
Wrap dough in plastic wrap and refrigerate for at least 24 hours but no more than 72 hours.
07 -
Let dough sit at room temperature until just soft enough to scoop, about 1 hour. Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper.
08 -
Divide the dough into 3-tablespoon sized balls using a large cookie scoop and place onto prepared baking sheets, allowing space for spreading.
09 -
Bake for 12 to 14 minutes, or until golden brown. Remove from oven and immediately sprinkle flaky sea salt on top of the cookies, if desired.
10 -
Let cookies cool for 2 minutes before transferring to wire racks to cool completely. Store in an airtight container at room temperature for up to 3 days.