Start by browning the butter, I have a whole blog post about how to brown butter if you'd like more information. Put the butter in a small saucepan and heat over medium heat. Once it has melted it will start making a 'crackling' sound, keep going, stirring occasionally.
When the crackling subsides a little, the butter will quickly start to turn a toasty brown color. Once the butter is brown and you can smell a lovely nutty aroma, remove the butter from the heat.
Pour the butter into your mixing bowl and set aside to cool while you prepare the pecans. Make sure you get all the little brown specks at the bottom of the pan - those are the toasted milk solids that add all the nutty flavor!
Toast the Pecans
Put the pecans in a dry frying pan and heat over medium heat. Let them toast, stirring occasionally until you can smell a lovely toasted pecan smell (about 5-7 minutes). Remove from the heat.
Take 2 tablespoons of the browned butter and add it into the pan with the pecans, toss the pecans to coat them in the brown butter and then let them sit in it while they cool for a few minutes.
Reserve a handful of pecans for decorating later, then transfer the rest to a chopping board and roughly chop them into small chunks.
Make the Pecan Cookies
The browned butter should have cooled slightly by now, it may still be slightly warm, but as long as it's not hot that's okay. Add both sugars to the browned butter and beat together until combined.
Add your egg and vanilla and then beat vigorously for one minute (medium-high speed if using an electric or stand mixer).
Sift in the dry ingredients, including the flour, baking soda, and salt and mix until combined.
Put the chopped pecans into the cookie dough. Mix them in by hand until evenly distributed.
Cover the bowl with plastic wrap and put the cookie dough in the fridge to chill for 30 minutes.Meanwhile, preheat the oven to 350°F / 180°C (160° fan-assisted) and line a cookie sheet with parchment paper.
Scoop balls of cookie dough with a medium cookie scoop onto the cookie sheet and then flatten them slightly with your hand. If you don't have a cookie scoop, you can use a tablespoon and roll into balls in your hands.
Press one or two pecans into the top of each cookie for decoration.Optional: Sprinkle with a little brown sugar and sea salt.
Bake for 10-12 minutes or until the edges are golden brown. Remove from the oven and let sit on the baking sheet for five minutes before transferring to a wire rack with a cookie lifter - or munch them while they are still warm and gooey!