Step 1

Prepare a baking sheet by lining with parchment paper.

Step 2

In a medium-small saucepan, melt butter and salt on low heat until melted completely.

Step 3

Add sugar and lecithin to the butter and whisk until smooth. Keep on low heat, stirring gently until the sugar crystals dissolve.

Step 4

Insert a candy thermometer and let the toffee come to 295-300°F (146-149°C). Keep the heat on low the whole time and gently stir occasionally (without scraping the upper sides of the pan) so that it doesn’t burn. See recipe notes for toffee troubleshooting.

Step 5

Pour toffee onto lined baking sheet and push it around with a spoon to form a thin toffee layer. Do not scrape the bottom of the pot out.

Step 6

Let the toffee cool completely and break it up into pieces. Store in an airtight container at room temperature or in the fridge for up to three weeks.

Step 7

Brown the butter in a medium saucepan. Melt the butter on medium-low heat until it starts to foam and simmer, stirring consistently so it doesn’t burn. The foam will subside and you will start noticing the bits of white milk solids start to turn toasty brown.

Step 8

Once it starts to foam again and turns golden brown immediately remove from heat. You don’t want it to burn!

Step 9

Transfer to a heat safe bowl and add 1 tbsp cold butter. Stir until melted and set aside to cool to room temperature.

Step 10

Add brown sugar, granulated sugar, and sea salt to the butter and whisk to break up any lumps.

Step 11

Add egg and vanilla into the batter and whisk until it thickens and becomes lighter.

Step 12

Sift flour and baking soda into the bowl. Fold just until there are no more dry streaks of flour.

Step 13

Add the toffee and chocolate and fold. Reserve a little bit of each for topping the cookies.

Step 14

Place the bowl in the freezer for 10 minutes to chill so that the cookie dough is more scoopable.

Step 15

Scoop the dough into balls onto a parchment lined cookie sheet or plate. I made 10 large cookies but you can use a smaller scoop for smaller cookies.

Step 16

Top the cookies with more chopped chocolate and toffee. Refrigerate for at least 45 minutes to chill completely or overnight.

Step 17

Preheat oven to 355°F (180°C). Place cookie dough balls onto a parchment lined baking sheet leaving 4” space in between each cookie. They will spread out quite a bit.

Step 18

Bake for 10-12 minutes for larger cookies or 8-10 minutes for medium cookies. The cookies are ready when the edges are slightly browned and set, and the middles are still soft.

Step 19

Push in the edges of the cookies to make them round again. Sprinkle with flaky salt. Let the cookies cool for at least 10 minutes on the baking sheet before transferring to a cooling rack or plate. They are very delicate and soft.