1 stick (4 ounces) butter, melted and slightly cooled
1/2 cup (100 grams) granulated natural cane sugar
1/2 cup (79 grams) packed dark brown sugar
1 large egg (50 grams)
1 teaspoon (5 ml) vanilla extract
1 cup (145 grams) plus 2 tablespoons (16 grams) whole wheat pastry flour
1/4 teaspoon (1 grams) baking soda
1/4 teaspoon (1 grams) fleur de sel
1 cup walnuts (100 grams), chopped
Preheat the oven to 375ºF. Line three baking sheets with parchment paper; set aside.
Add the butter and sugars to a deep bowl. Beat on high speed until well combined, about 2 minutes. Add the egg and vanilla, and beat on high speed until light and fully, 2 to 3 minutes.
Add the flour, baking soda and fleur de sel to the bowl. On low speed, mix until the flour is completely mixed in, about 1 minute. Add the walnuts and beat on medium high speed 30 seconds to 1 minute, until well mixed.
Drop generous tablespoonfuls of dough, three inches apart on the prepared baking sheets (you should be able to fit six per sheet). Bake for 14 minutes, until the edges are golden and the bottoms are lightly browned. Remove sheet from the oven and let the cookies cool on the pan for 2 minutes. Using a spatula, transfer the cookies to a wire rack to finish cooling completely.