Begin by creaming together 1 cup of room temperature unsalted butter and 1 cup of granulated sugar in a large mixing bowl.

Gradually add 2 tablespoons of instant espresso powder, 1 teaspoon of vanilla extract, and a pinch of sea salt into the butter-sugar mixture.

In a separate bowl, whisk together 2 cups of all-purpose flour and 1 tablespoon of cornstarch until well blended.

Gently fold in 1 cup of chocolate-covered toffee chunks into the cookie dough using a spatula.

Shape the dough into a disc and wrap it tightly in parchment paper. Chill the dough in the refrigerator for at least 1 hour.

While the dough is chilling, preheat your oven to 350°F (175°C).

Once chilled, roll out the dough on a floured surface or parchment paper to your desired thickness.

Place your baking sheet in the preheated oven and bake the cookies for 18-20 minutes or until lightly golden around the edges.

After baking, allow the cookies to cool on the baking sheet for about 5 minutes before transferring them to wire racks to cool completely.