Step 1: Prep Your Ingredients
Start by preheating your oven to 350°F (175°C). Line two baking sheets with parchment paper.

Step 2: Mix the Dry Ingredients
In a medium bowl, whisk together the flour, baking soda, salt, cinnamon, and nutmeg. Set aside.

Step 3: Cream Butter and Sugars
In a large mixing bowl, beat together softened butter, brown sugar, and granulated sugar until light and fluffy (about 2–3 minutes). Add in eggs one at a time, followed by vanilla extract.

Step 4: Combine Wet and Dry
Slowly add the dry ingredients to the wet, mixing just until combined. Fold in the oats and raisins (and nuts, if using) with a spatula.

Step 5: Chill the Dough
For the chewiest cookies, chill the dough for 30–60 minutes. This helps control spread and intensifies the flavor.

Step 6: Scoop and Bake
Scoop the dough into 2-tablespoon-sized balls and place them 2 inches apart on the baking sheets. Bake for 10–12 minutes or until the edges are golden and the centers still look slightly soft.

Step 7: Cool and Enjoy
Let cookies cool on the sheet for 5 minutes before transferring to a wire rack. Serve warm or store for later—if they last that long!