Preheat your oven to 350°F and position racks in the upper and lower thirds so you can bake two sheets simultaneously. While the oven heats, measure out all your ingredients into separate bowls: brown sugar, granulated sugar, flour, baking soda, cinnamon, and salt. I like to plump my raisins by soaking them in warm water for 5 minutes while I prep everything else—this keeps them moist and flavorful in the finished cookies. Pat them dry with a paper towel before adding them to the dough. Having everything measured and ready ensures smooth mixing without interruptions.

In a large bowl, combine the softened butter, brown sugar, and granulated sugar. Using an electric mixer on medium speed, beat for 2-3 minutes until the mixture is light, fluffy, and noticeably pale. This creaming process incorporates air into the dough, which helps the cookies spread evenly and develop a tender crumb. You should see the color lighten and the texture become almost mousse-like.

Add the room-temperature eggs and vanilla extract to the creamed butter and sugar mixture. Beat on medium speed for 1-2 minutes until the eggs are fully incorporated and the mixture appears smooth and homogeneous. Room-temperature eggs emulsify more smoothly with the fat, creating a better texture in the final cookies. Scrape down the sides of the bowl with a spatula to ensure everything is evenly combined.

In a separate bowl, whisk together the flour, baking soda, cinnamon, and salt. This combines all your dry ingredients evenly and prevents baking soda streaks in your cookies. Add the dry ingredient mixture from Step 1 to the wet ingredients from Step 3, mixing on low speed just until combined—don't overmix, as this can toughen the dough. The mixture should come together without any visible flour streaks, but you want to preserve the tender crumb structure you developed during creaming.

Using a wooden spoon or sturdy spatula, fold the old-fashioned rolled oats and plumped raisins (from Step 1) into the dough until evenly distributed. Folding rather than beating keeps the dough tender by minimizing gluten development. The cookies should have oats and raisins throughout without any pockets of just dough. I find that slightly moist oats from folding in the plumped raisins add extra moisture and chewiness to the final cookies.

Drop rounded tablespoon-sized portions of dough onto baking sheets, spacing them about 2 inches apart to allow for spreading. Bake for 10-12 minutes on the preheated oven racks (use both the upper and lower thirds) until the edges are golden but the centers still look slightly underbaked. The cookies will continue to set as they cool, resulting in crispy edges and a chewy center. Rotate the baking sheets halfway through baking if your oven has hot spots.

Allow the cookies to rest on the baking sheets for 5 minutes—this lets them set up enough to handle without falling apart, while still retaining the chewy texture that makes these cookies special. Transfer the cookies to a wire rack to cool completely. Store them in an airtight container at room temperature for up to 5 days.