1. Preheat the oven to 350°F (175°C). Prepare two large baking sheets by lining them with parchment paper.

Toast the pecans:

1. Spread the pecans on a baking sheet and toast in the preheated oven for approximately 5–7 minutes, or until fragrant and lightly browned. Shake the baking sheet halfway through for even toasting. Allow the pecans to cool completely before chopping them coarsely.

Cream the butter and sugars:

1. In the bowl of a stand mixer fitted with the paddle attachment, cream together the softened butter, brown sugar, and granulated sugar on medium-high speed until light and fluffy, about 2–3 minutes.

Add the eggs and vanilla:

1. Reduce the mixer speed to low. Add the eggs one at a time, mixing thoroughly after each addition. Incorporate the vanilla extract.

Combine the dry ingredients:

1. In a separate medium bowl, sift together the flour, baking powder, cinnamon, and salt. Gradually add the dry ingredients to the butter mixture, mixing until just combined. Avoid overmixing.

Add the oats, raisins, and pecans:

1. Fold in the oats, raisins, and chopped toasted pecans using a spatula or wooden spoon until evenly distributed.

Portion and bake:

1. Using a cookie scoop or heaping tablespoon, drop dough onto the prepared baking sheets, spacing cookies about 2 inches apart. Slightly flatten each dough mound using damp fingertips.
2. Bake the cookies for 11 to 13 minutes, or until the edges are lightly golden and the centers are set. Remove from the oven and allow the cookies to cool on the baking sheet for several minutes before transferring them to a wire rack to cool completely.