Preheat your oven to 425°F (218°C). Line a 9x13-inch baking dish with parchment paper.

Arrange the saltine crackers in a single layer at the bottom of the pan.

In a medium saucepan over medium-high heat, melt the butter and brown sugar together, stirring occasionally until it reaches a boil. Lower the heat and boil for an additional 4-5 minutes without stirring.

Remove from heat and pour the mixture over the crackers ensuring they are evenly covered.

Bake for about 4-5 minutes until bubbly.

Remove the pan from the oven, sprinkle the chocolate chips over the toffee, and let them sit for a few minutes to soften. Use a rubber spatula to spread the melted chocolate over the toffee.

Sprinkle with sea salt if desired. Transfer the pan to the freezer while preparing the cookie dough.

In a medium saucepan, place the remaining butter over medium heat. Swirl as it melts and continue stirring for about 5 minutes until it turns golden and nutty-smelling.

Remove from heat and let it cool slightly for 10 minutes.

In a large bowl, whisk together the flour and baking soda.

Once the browned butter has cooled, add both sugars and mix well. Incorporate the eggs and vanilla until blended.

Pour the wet ingredients into the dry flour mixture and stir until combined.

Place the dough in the freezer for a few minutes while chopping the toffee layer from the freezer into small pieces.

Stir most of the toffee into the cookie dough (save some for topping). Cover the dough and chill for at least 2 hours or up to 3 days.

Preheat the oven to 350°F (177°C).

Scoop the dough into 2-tablespoon-sized balls and place them on a lined baking sheet a few inches apart.

Bake for 8-10 minutes until the edges are golden brown and the centers are just set.

Add your reserved toffee pieces on top of the cookies after pulling them from the oven. Allow to cool on the baking sheet for about 5 minutes before transferring to a wire rack to cool completely.