Before you start mixing, gather all ingredients and ensure your butter is at room temperature (about 70°F) so it creams properly. In a small bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt to combine evenly and break up any lumps. If your raisins seem dried out, soak them in warm water for 10 minutes and drain well before using. This prep work ensures smooth mixing and prevents overmixing later, which can toughen the cookies.

In a large mixing bowl, combine the softened butter, granulated sugar, and packed brown sugar. Beat on medium speed for 3 minutes until the mixture is light, fluffy, and pale in color. This creaming process incorporates air into the butter, which helps the cookies rise and creates a tender crumb. You'll know it's ready when it looks almost like frosting.

Add the room-temperature egg and vanilla extract to the creamed mixture and beat for 1 minute until fully incorporated. Add the dry ingredient mixture from Step 1 and beat for 2 minutes until just combined—you want to avoid overmixing at this stage, as it can develop gluten and make the cookies tough. I like to use freshly ground cinnamon here since it has so much more flavor than the pre-ground version; the difference is really noticeable in the final cookies.

Add the rolled oats and raisins to the dough and mix on low speed or fold by hand just until everything is evenly distributed. Transfer the dough to the refrigerator and chill for 30–60 minutes. This resting period allows the flour to fully hydrate and the flavors to meld together, which improves the texture and taste of the baked cookies.

About 15 minutes before you're ready to bake, preheat your oven to 350°F and prepare your baking sheets by lining them with parchment paper or silicone baking mats. This gives the oven time to reach a stable temperature and prevents the dough from warming up too much while you scoop cookies.

Remove the chilled dough from the refrigerator and scoop heaping 2-tablespoon portions onto the prepared baking sheets, spacing them about 2 inches apart to allow for spreading. Bake for 10–12 minutes until the edges are lightly golden but the centers still look slightly underdone—this is the key to keeping them chewy rather than crispy. I always pull them out when they still look a little soft in the middle because they continue to cook slightly as they cool, resulting in that perfect old-fashioned texture.

Let the cookies cool on the baking sheet for 5 minutes—this allows them to set enough to handle without falling apart. Then transfer them to a wire cooling rack to cool completely. Cooling on the rack (rather than the sheet) prevents the bottoms from becoming overly crispy from residual heat.