Melt 2 tablespoons of butter in a large skillet over medium heat. Add the pecans, sugar, and salt.
Continue cooking over medium heat, stirring frequently, until the pecans are toasted and the sugar sticks to them (about 7 or 8 minutes). Set aside to cool.
For the cookies:
Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper or silicone liners.
Whisk together the flour, baking powder, baking soda, and salt. Stir in the oats. Set aside.
Using an electric mixer on medium speed, beat the butter and brown sugar until light and fluffy. Add the eggs, one at a time, mixing well after each addition. Mix in the vanilla.
Reduce the mixer speed to low. Gradually add the flour mixture, mixing just until combined. Stir in the pecans and the caramel pieces.
Drop the dough by 3-tablespoon portions onto the prepared pans, leaving about 2 inches between cookies. Flatten the top of each cookie slightly. Bake 12 to 16 minutes, or until the edges are browned.
Cool the cookies on the pans for 5 minutes. Then transfer them to a wire rack to cool completely.
Notes
*I use mostly pecan halves, but it's fine to have some smaller pieces as well. The weight is an estimate, as it will vary deepening on your ratio of halves to pieces.
** I recommend cutting each of the caramels into several small pieces. I usually make two parallel cuts and then 2 cuts perpendicular to those to make 9 smaller pieces (like a hashtag). Larger pieces of caramel tend to harden up in the cookies after they're baked. If you have access to caramel bits, these should work, too. You'll need about 2 ounces, or about 3 to 4 tablespoons.