Making the Toffee

Start by preparing the toffee. Preheat the oven to 425°F (220°C) and line a 9×13-inch baking dish with parchment paper. Lay the saltine crackers in a single layer, covering the bottom of the pan. Set the pan aside while you make the caramel sauce.

In a medium saucepan, melt the butter and brown sugar over medium-high heat. Stir occasionally as the butter melts, and then let the mixture come to a boil. Once boiling, reduce the heat to medium and allow the mixture to simmer for 4-5 minutes. Do not stir during this time, as you want the sugar and butter to bubble and create a smooth caramel. The sugar should completely dissolve, and the caramel should thicken slightly.

After 4-5 minutes, remove the saucepan from the heat and carefully pour the caramel over the saltine crackers in an even layer. Use a wooden spoon or rubber spatula to spread the caramel and ensure it covers all the crackers. Place the pan in the preheated oven and bake for about 4-5 minutes, until the toffee is just bubbly. Once done, remove it from the oven.

Sprinkle the semisweet chocolate chips over the toffee and allow them to melt for a few minutes. Once the chocolate is soft, use a spatula to spread it evenly over the caramel. Optionally, sprinkle some sea salt on top to enhance the sweet-salty flavor profile. Afterward, transfer the toffee to the freezer while you prepare the cookie dough.

Browning the Butter for the Cookies

Now, let’s focus on the cookies. Place the unsalted butter in a medium saucepan over medium heat. As the butter melts, continue stirring constantly. After about 5 minutes, the butter will start to bubble and foam. The milk solids will gradually begin to toast, and the butter will turn a golden brown color. This step gives the butter a nutty, rich flavor that adds complexity to the cookies. Be careful not to let it burn. Once browned, remove the butter from the heat and let it cool slightly (about 10 minutes).

Making the Cookie Dough

While the butter cools, whisk together the flour and baking soda in a large bowl. The baking soda helps the cookies rise while baking, giving them a soft and chewy texture. Once the browned butter has cooled down slightly, add the brown sugar and granulated sugar to the saucepan and whisk to combine. Then, add the eggs one at a time, whisking well after each addition, followed by the vanilla extract. The mixture should be smooth and creamy.

Pour the wet ingredients into the flour mixture and stir using a rubber spatula. The dough will initially appear dry, but keep stirring, and it will come together into a thick, cohesive dough.

Assembling the Cookies

Now, it’s time to bring everything together. While the dough chills, break the toffee into small pieces. You can use a sharp knife or break it up with your hands—just be careful not to melt the chocolate. Add almost all of the toffee pieces to the dough, saving some for topping the cookies later. Stir the toffee into the dough, ensuring it is evenly distributed. Cover the dough with plastic wrap and chill it in the refrigerator for at least 2 hours (or up to 3 days). Chilling the dough helps prevent the cookies from spreading too much while baking.

Baking the Cookies

Once the dough has chilled, preheat the oven to 350°F (175°C) and line a large baking sheet with parchment paper or a silicone baking mat. Use a cookie scoop to form 2-tablespoon-sized balls of dough and place them on the prepared baking sheet, spacing them about 2 inches apart. Bake the cookies for 8-10 minutes, or until the edges are golden brown, and the tops are just set. The cookies should look slightly soft in the center but will firm up as they cool.

Once out of the oven, immediately sprinkle the reserved toffee bits on top of each cookie. Let the cookies cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.