• Line two cookie sheets with parchment paper. You can just line a work servace is you prefer. I use cookie sheets so I can easily move them.
• Combine oats and chopped pecans in a large mixing bowl. Set aside.
• In a large saucepan, melt butter with maple syrup over medium-high heat. Stir constantly and cook until the mixture reaches 240°F on a candy thermometer (this is crucial, so be patient—if it doesn't reach this temperature, the cookies won't set properly). The mixture will bubble up, so use a large enough pan to prevent it from boiling over.
• Once the syrup mixture hits the right temperature, immediately pour it over the oats and pecans, and stir well to combine.
• Use a cookie scoop to form 24 cookies on the prepared cookie sheets.
• Flatten each cookie with a greased measuring cup or gently shape with your hands. Place one pecan on each cookie while they are still warm.
• Let the cookies rest for 1 hour, then flip and let sit for another hour.

For the Maple Glaze:

• Mix powdered sugar and maple syrup in a bowl until smooth.
• Transfer the glaze to a zip-lock bag, snip off a small corner, and drizzle over the cookies.