Line a large surface, such as your kitchen table or countertop, with parchment paper. This makes cleanup easy and keeps the cookies from sticking.

In a large mixing bowl, combine the oats and chopped pecans. Toss until evenly distributed, then set aside.

Slice the butter into 2-tablespoon pieces. Add the butter and maple syrup to a medium saucepan.

Place over medium-high heat and stir constantly until the mixture reaches 240°F on a candy thermometer (about 10 minutes). Hitting the correct temperature is essential for the cookies to set properly.

Once the syrup mixture reaches 240°F, immediately pour it over the oat and pecan mixture. Stir quickly and thoroughly to coat every oat and nut before the syrup begins to set.

Using a 1.9-inch cookie scoop (or smaller, based on your preference), scoop mounds of the mixture onto the prepared parchment paper.

Lightly spray a flat-bottomed measuring cup with nonstick cooking spray and press down on each mound to flatten. If needed, shape the edges with a gloved hand for a neat finish.

Let the cookies sit for 1 hour, then flip them gently with a gloved hand. They may still feel slightly tacky - this is normal. Allow them to rest for another hour.

Optionally, top each cookie with a whole pecan for extra crunch and a pretty presentation. Enjoy!