Make the Toffee

Preheat oven to 425°F (220°C). Line a 9×13-inch pan with parchment paper.

Arrange the saltine crackers in an even layer in the pan.

Melt butter and brown sugar in a saucepan over medium-high heat. Bring to a boil, then reduce to medium and boil 4–5 minutes without stirring.

Pour the caramel evenly over the crackers. Bake 4–5 minutes, until bubbly.

Remove from oven, sprinkle with chocolate chips, and let sit until melted. Spread evenly and sprinkle with sea salt if desired.

Transfer to the freezer while you prepare the cookie dough.

Brown the Butter

Melt butter in a saucepan over medium heat, stirring constantly.

Cook for about 5 minutes until golden brown with a nutty aroma.

Remove from heat and cool for 10 minutes.

Make the Dough

Whisk flour and baking soda in a large bowl.

Whisk sugars into the slightly cooled browned butter.

Add eggs and vanilla; whisk until smooth.

Stir wet ingredients into dry ingredients until combined.

Briefly chill dough while chopping the toffee.

Assemble & Bake

Chop frozen toffee into small pieces.

Fold most of the toffee into the dough, reserving some for topping.

Cover and chill dough for at least 2 hours (up to 3 days).

Preheat oven to 350°F (175°C). Line a baking sheet with parchment.

Scoop dough into 2-tablespoon balls, spacing apart.

Bake 8–10 minutes, until edges are golden and centers just set.

Top with reserved toffee. Cool 5 minutes on pan, then transfer to a rack.