Preheat and prep. Set your oven to 350°F (175°C). Line two baking sheets with parchment paper or silicone mats to prevent sticking and promote even browning.

Measure accurately. For best results, spoon flour into the measuring cup and level it off. This helps avoid dense cookies from packed flour.

Cream the butter and sugars. In a large bowl, beat 1 cup (2 sticks) softened unsalted butter with 3/4 cup brown sugar and 1/2 cup granulated sugar until light and fluffy, about 2–3 minutes. This step builds structure and gives you that tender chew.

Add eggs and vanilla. Beat in 2 large eggs, one at a time, then mix in 2 teaspoons vanilla extract. Scrape the bowl so everything mixes evenly.

Whisk dry ingredients. In a separate bowl, whisk 1 1/2 cups all-purpose flour, 1 teaspoon baking soda, 1 teaspoon ground cinnamon, and 1/2 teaspoon fine salt.

Combine wet and dry. Add the dry mixture to the butter mixture and mix on low just until combined. Avoid overmixing here to keep the cookies soft.

Stir in oats (and extras). Fold in 3 cups old-fashioned rolled oats. If using add-ins, fold in up to 1 1/2 cups total—try 1 cup raisins or chocolate chips plus 1/2 cup chopped nuts. Don’t overload the dough.

Chill briefly (optional but helpful). If your kitchen is warm, chill the dough for 15–20 minutes. Chilling prevents excessive spread and enhances flavor.

Scoop and space. Use a 1 1/2-tablespoon scoop (about the size of a rounded tablespoon). Place scoops 2 inches apart on prepared sheets. For thicker cookies, keep rounded mounds. For slightly thinner cookies, gently press the tops.

Bake. Bake 10–12 minutes, rotating pans halfway. Pull them when the edges are set and lightly golden, and the centers still look a bit soft. They’ll finish setting as they cool.

Cool. Let cookies sit on the baking sheet for 5 minutes, then move them to a wire rack to cool completely. This helps lock in that chewy center.