Ingredients

1 cup (226g) unsalted butter, softened

1 cup (200g) light brown sugar, packed

½ cup (100g) granulated sugar

2 large eggs, room temperature

1½ teaspoons vanilla extract

1¾ cups (215g) all-purpose flour

2 teaspoons cornstarch

1 teaspoon baking soda

¾ teaspoon salt

¾ teaspoon ground cinnamon

3 cups (285g) old-fashioned rolled oats

1½ cups mix-ins (chocolate chips, raisins, or nuts), optional

Instructions

Step 1: Beat the softened butter in a large bowl using an electric mixer for about 30 seconds until smooth.

Step 2: Add the brown sugar and granulated sugar, then beat for 2–3 minutes until light and fluffy, scraping down the sides of the bowl as needed.

Step 3: Beat in the eggs one at a time, then add the vanilla extract and mix well.

Step 4: In a separate bowl, whisk together the flour, cornstarch, baking soda, salt, and cinnamon.

Step 5: Gradually add the flour mixture to the butter mixture, mixing on low speed until just combined.

Step 6: Stir in the oats until evenly distributed. If using mix-ins, fold them in now.

Step 7: Cover the dough and refrigerate for at least 30 minutes or up to 3 days.

Step 8: Preheat the oven to 375°F (190°C) and line baking sheets with parchment paper.

Step 9: Scoop chilled dough using a 2-tablespoon cookie scoop and place on the prepared baking sheets, spacing cookies about 2 inches apart.

Step 10: Bake for 10–12 minutes until the edges are lightly golden but the centers still look slightly underdone.

Step 11: Allow the cookies to cool completely on the baking sheet before removing.

Tips & Variations

For chewier cookies, gently underbake by removing them as soon as edges brown but centers remain soft.

Try adding 1 teaspoon of ground nutmeg or swapping cinnamon for pumpkin pie spice for a warm flavor twist.

Substitute half the all-purpose flour with whole wheat flour for a nuttier taste and added fiber.

Use a mix of raisins and chopped nuts for extra texture and sweetness.

If you prefer crispier cookies, flatten dough balls slightly before baking.

Storage

Store cooled oatmeal cookies in an airtight container at room temperature for up to 5 days. For longer storage, freeze the baked cookies in a sealed container or freezer bag for up to 3 months. To reheat, warm cookies in a low oven (300°F/150°C) for 5–7 minutes or microwave for about 15 seconds to restore softness.

FAQs

Can I make the dough ahead of time?

Yes, chilling the dough for at least 30 minutes enhances the flavor and texture. You can refrigerate it for up to 3 days or freeze it for longer storage before baking.

What can I use instead of cornstarch?

If you don’t have cornstarch, you can substitute with an equal amount of arrowroot powder or replace it with an additional 2 tablespoons of all-purpose flour to help with the cookie’s tenderness.