Preheat your oven to 375 degrees and line two cookie sheets with a silpat or parchment paper.
In a large bowl, using an electric hand mixer, beat together the coconut oil and coconut sugar until the sugar is moistened. Add in the egg white and vanilla extract and beat until well combined.
Add the pecan flour, baking powder and salt to the bowl. Stir until well combined. Place the bowl into the refrigerator to chill.
Spread the pecans onto a small baking sheet and place into the oven to toast while you make the rest of the filling.These only take 5-10 minutes, watch them closely so they don't burn. You will smell them when they are ready! Once cooked, reduce the oven temperature to 350 degrees.
While the pecans cook,iIn a small pot set over medium heat, stir together the coconut sugar, maple syrup, coconut oil and salt until combined. Bring to the mixture to a boil.
Once boiling, stir constantly for 1 minute. Then, remove the pot from the heat and let the mixture stand for 3 minutes.
Once the mixture has stood, dice the pecans and add them, along with the egg yolk, into the filling mixture. Stir until well combined.
Drop the chilled cookie dough by lightly heaping 1 Tbsp balls onto the prepared cookie sheets leaving a generous amount of space between them, as they do spread out a lot. use your thumb to press a hole into the center of each cookie.
Spoon 1 tsp of the filling into the hole, lightly pressing it in, and letting some spill over top of the cookie. Make sure to re-form the cookie slightly, as you want them to have nice, high sides before baking. Place back into the refrigerator to chill for 15 minutes.
Once chilled, bake until the cookies are flat, and the edges are JUST golden, about 12-13 minutes for more soft and chewy cookies, or 15-16 minutes for cookies with crispy edges and softer centers.* Let cool on the pan for 5 minutes and then transfer to a wire rack to cool completely.
*If you can only fit one pan at a time, keep the other one in the refrigerator until ready to use.