Start by preheating your oven to 350°F (175°C). This ensures that your cookies bake perfectly right from the beginning.

Line a couple of baking sheets with parchment paper. This not only prevents sticking but also ensures even baking.

In a large mixing bowl, combine 1 cup of creamy unsalted butter, 1/2 cup of fine granulated sugar, and 1 cup of dark brown sugar. Beat them together until the mixture is light and fluffy. This step usually takes around 3 minutes using an electric mixer.

Once the butter and sugars are well mixed, incorporate 2 teaspoons of vanilla extract, 1 large egg, and 1 egg yolk. Beat these into the mixture until just combined.

In a different bowl, mix together 1 cup of artisanal bread flour, 3/4 cup of all-purpose flour, 2 teaspoons of coarse kosher salt, 1 teaspoon of baking soda, and 1 teaspoon of espresso powder. Stir these until well blended.

Slowly fold the dry ingredients into the wet mixture. Use a spatula or a wooden spoon to incorporate everything until just combined.

Add 1 cup of semi-sweet chocolate chunks and 1/2 cup of chopped toasted walnuts. Gently fold them into the dough. Here’s where you’ll start to smell that delightful cookie aroma wafting through your kitchen!

Using a tablespoon or cookie scoop, drop equal amounts of dough onto your prepared baking sheets, spacing them about 2 inches apart.

Sprinkle a little sea salt over the tops of each cookie before they go into the oven. This step enhances the flavor.

Place the baking sheets in your preheated oven. Bake for 10-12 minutes. Remember, it’s better to slightly underbake than overbake for that chewy texture.

Remove the cookies from the oven once they’re golden around the edges and still soft in the center. Let them cool on the baking sheets for a few minutes, then transfer them to wire racks to cool completely.