Makes about 20
- 1 cup (2 sticks) unsalted butter
- 2 cups all-purpose flour
- 1 teaspoon baking soda
- ¾ teaspoon kosher salt
- 1 cup (packed) dark brown sugar
- ⅓ cup granulated sugar
- 2 large eggs, room temperature
- 2 teaspoons vanilla extract
- 2 chocolate toffee bars, chopped into ¼-inch pieces (preferably Skor)
- 1½ cups chocolate wafers (discs, pistoles, fèves; preferably 72% cacao)
- Flaky sea salt
- Cook butter in a medium saucepan over medium heat, stirring often, until butter foams, then browns, 5–8 minutes. Transfer brown butter to a large bowl; let cool slightly.
- Whisk flour, baking soda, and kosher salt in a medium bowl.
- Add brown sugar and granulated sugar to cooled butter. Using an electric mixer on medium speed, beat butter mixture, scraping down sides of bowl, until incorporated, about 1 minute. Add eggs and vanilla and continue to beat until mixture lightens and begins to thicken, about 30 seconds. Reduce mixer speed to low; add dry ingredients and beat, scraping down sides and bottom of bowl, until just combined. Add candy and chocolate wafers and mix to combine with a spoon or spatula. Let sit at room temperature at least 30 minutes to hydrate flour; dough will look very loose but will thicken as it sits.
- Arrange a rack in center of oven; preheat to 375°. Line a rimmed baking sheet with parchment paper. Using a 1½-oz. ice cream scoop, portion dough and transfer to prepared sheet, spacing about 3½” apart (alternatively, form dough into ping pong ball-sized pieces with your hands). Do not flatten; cookies will spread as they bake. Sprinkle with sea salt.
- Bake cookies until edges are golden brown and firm but centers are soft, 9–11 minutes. Let cool on sheets 10 minutes, then transfer to a wire rack and let cool completely.
- Do Ahead: Cookie dough can be made 3 days ahead; cover and chill. Let dough come to room temperature before baking.