Line rimmed baking sheets with parchment paper.

In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugars at medium speed until light and fluffy, 2 to 3 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating well after each addition and stopping to scrape sides of bowl. Beat in vanilla.

In a medium bowl, whisk together oats, flour, cinnamon, baking soda, salt, and baking powder. With mixer on low speed, gradually add oats mixture to butter mixture, beating just until combined. Stir in raisins. Using a 3-tablespoon spring-loaded scoop, scoop dough (about 52 grams each), and place about 2 inches apart on prepared pans. Refrigerate until firm, about 30 minutes.

Preheat oven to 325°F (170°C).

Bake until edges are just set, about 18 minutes. (Centers will still seem a little soft.) Let cool on pans for 5 minutes. Remove from pans, and let cool completely on wire racks. Store in an airtight container for up to 3 days.