Ingredients
2 sticks (1 cup) butter, cubed and kept cold
150g granulated sugar
165g dark brown sugar
2 eggs plus 1 egg yolk
½ teaspoon vanilla extract
140g unbleached all-purpose flour
150g bread flour
1 teaspoon baking soda
40g cornstarch
½ teaspoon salt
½ teaspoon espresso powder
10 oz semi-sweet chocolate chips, plus more for topping
5 oz milk chocolate chips, plus more for topping
4 oz toffee bits, plus more for topping
Flaky sea salt, for finishing
Instructions
- Cube butter and refrigerate until ready to use.
- Weigh and mix both sugars together in a bowl.
- Crack eggs into a bowl or liquid measuring cup and refrigerate until ready to use.
- In a separate bowl, whisk together both flours, baking soda, cornstarch, salt, and espresso powder.
- In a stand mixer, cream cold butter briefly. Add sugars and mix for 2-3 minutes until incorporated and beginning to look fluffy.
- Add eggs one at a time, fully incorporating each before adding the next. Add vanilla extract.
- Add dry ingredients in small batches, mixing just until incorporated. Do not over mix.
- By hand, fold in chocolate chips and toffee bits.
- Scrape dough into an airtight container and refrigerate overnight.
- When ready to bake, preheat oven to 350°F.
- Mix together extra chocolate chips and toffee bits for topping.
- Scoop 2.5 oz portions of dough and roll into tall balls. Press the top of each ball into the chip and toffee mixture.
- Bake 12-14 minutes, watching from the 12-minute mark. Edges should look set but centers will look slightly underdone.
- Remove from oven and immediately sprinkle with flaky sea salt. Leave on the pan for 10-15 minutes before transferring to a cooling rack.
Notes
Unbaked dough keeps in the refrigerator for up to one week. Baked cookies keep at room temperature for 3-4 days.