Please note: You will need a stand mixer fitted with a paddle attachment and two baking sheets.

Preheat your oven to 350°F (175°C). Line the baking sheets with parchment paper.

Using your fingers, rub the sugar and rosemary together in a small bowl. This will help infuse the sugar with the flavour of the rosemary. Set aside.

In a bowl, whisk together the flour, cocoa powder, salt, and baking soda. Set aside.

Place the butter, sugar-rosemary mixture, and vanilla in a stand mixer bowl. Cream on medium speed for 1 to 2 minutes, until white and fluffy, scraping down the sides of the bowl a few times.

Add the egg and beat until well incorporated and the batter is fluffy.

Turn the mixer down to low, add the flour mixture, and mix until just combined. Then remove the bowl from the mixer and fold in the chocolate chunks.

Using an ice cream scoop, a spoon, or your hands, shape the dough into 1- to 2-inch balls. Arrange on the lined baking sheets 2 inches apart.

Sprinkle a pinch of fleur de sel on top of each cookie.

Bake for 12 to 13 minutes. The secret to chewy cookies is to remove them from the oven when they still look soft, slightly underbaked, and a little cracked on top. Let them rest on the baking sheet for 15 minutes before transferring them to a cooling rack.

Storage: These cookies will keep at room temperature for up to five days.