Cream the butter and sugars in a large bowl or in the bowl of a stand mixer, until lighter in color and texture. Add the vanilla extract and eggs to the butter mixture and mix on medium speed until fully incorporated, scraping down the sides of the bowl as needed.
Slowly add the flour, salt, baking powder, and baking soda, mixing on low speed until just combined. There should be large streaks of flour still remaining. Add the chocolate fèves and mix briefly until just incorporated.
Cover the dough with plastic wrap or place in an airtight container, and then refrigerate it for 48 hours. Aging the dough melds the flavors and creates nutty caramel notes that won’t develop otherwise.
When you are ready to bake the cookies, preheat the oven to 350°Remove the dough from the refrigerator about 30 minutes before scooping to soften it slightly. Line 2 sheet trays with parchment paper. Scoop balls of dough about 2 inches in diameter and place them about 2 inches apart on the trays. You can use a heaping #30 (1 fluid ouncscoop if you have one.
Bake for about 15 minutes or until the cookies are browned and caramelized along the edges and centers are just set.
Top each cookie with a sprinkling of the vanilla-infused Maldon salt, about ¼ teaspoon. Cool on trays for 2 minutes and transfer to a rack to cool completely, or eat warm. Repeat with remaining cookie dough. Keep in an airtight container for up to 3 days.