• This cookie makes 24 large cookies or 60 small cookies. Use a 3-tablespoon cookie scoop to make the large cookies.

For the Hazelnut Toffee

• This recipe for hazelnut toffee makes 4 cups of chopped hazelnut toffee or 2-1/2 pounds of toffee, if you use this recipe to make toffee to gift for others.
• Line a half baking sheet with Silpat.
• Place the sugar, water, butter and salt in a 3-quart saucepan. Bring the mixture to a boil over medium-high heat, whisking constantly. Boil the mixture until it reaches 300 degrees F. Use a candy thermometer to monitor the temperature.
• Remove the pan from the heat and immediately add the vanilla extract and toasted hazelnuts. Stir with a heat-proof silicon spatula and then scrape onto the Silpat. Use the spatula to spread the toffee across the surface. Allow the mixture to cool and harden. When it is completely cool chop it into 1/2-inch pieces.

For the Chocolate Chip Cookies

• Place the all-purpose flour, baking soda and salt in a bowl and whisk together.
• Place the butter, the white, brown sugars, and vanilla in the bowl of stand mixer and beat with the paddle attachment on medium speed until it is lighter in color and fluffy, about 3 minutes. Add the eggs one at a time, beating after each addition just until incorporated. Scrape the sides and bottom of the bowl.
• Add the flour mixture and mix on low speed and mix just until flour is blended in. Add the chopped chocolate and mix on low speed until chocolate appears evenly distributed. Add 2-3 cups of the chopped hazelnut toffee and mix on low speed until incorporated. Place the cookie dough in a bowl and refrigerate for 24-48 hours.
• Preheat the oven the 375 degrees F and line two baking sheets with parchment paper or Silpat. Remove the cookie dough from the refrigerator and allow it to sit a room temperature for 5-10 minutes to make it easier to scoop.
• Use a 3-tablespoon cookie scoop to drop balls of dough unto the cookie sheets. Bake the cookies for 10 minutes. If the cookies have spread into odd shapes use an offset palette knife to reshape the cookies into round shapes. Bake for another 1-2 minutes depending on how dark you like your cookies.
• As soon as the cookies come out of the oven sprinkle the center with flaky sea salt.
• Cool the cookies for about 1-2 minutes on the cookie sheet and then transfer to a wire rack to cool completely.