Peanut Butter Banana Oatmeal Cookies

Why You’ll Love This Recipe

• Hearty, chewy cookies packed with oats, peanut butter, and banana for a truly satisfying bite.
• Perfect way to use up that lone overripe banana sitting on the counter.
• One-bowl friendly and ready in about 30 minutes, start to finish.
• Not overly sweet, with cozy cinnamon and optional chocolate chips for a comforting treat.

Grocery List

• Produce: 1 large ripe banana
• Dairy: Unsalted butter, 1 large egg
• Pantry: Creamy peanut butter, old-fashioned rolled oats, all-purpose flour, light brown sugar, granulated sugar, baking soda, ground cinnamon, fine salt, vanilla extract, semisweet chocolate chips (optional), roasted peanuts (optional)

Full Ingredients

Cookie Dough

• 1 large ripe banana, mashed (about 1/2 cup / 120 g)
• 1/2 cup (130 g) creamy peanut butter (not natural drippy style if possible)
• 1/4 cup (56 g) unsalted butter, melted and slightly cooled
• 1/2 cup (100 g) packed light brown sugar
• 2 tbsp (25 g) granulated sugar
• 1 large egg, at room temperature
• 1 tsp pure vanilla extract
• 1 cup (100 g) old-fashioned rolled oats
• 3/4 cup (95 g) all-purpose flour
• 1/2 tsp baking soda
• 1/2 tsp ground cinnamon
• 1/4 tsp fine sea salt (use 1/8 tsp if your peanut butter is very salty)

Optional Mix-Ins

• 1/2 cup (85 g) semisweet chocolate chips or chunks
• 1/4 cup (30 g) chopped roasted peanuts

Step-by-Step Instructions

Step 1: Prep your oven and pans

Preheat your oven to 350°F (175°C). Line two large baking sheets with parchment paper or silicone baking mats. This helps the cookies bake evenly and prevents sticking without the need for extra greasing.

Position the oven racks in the upper and lower thirds of the oven so you can bake two trays at once, rotating them halfway through for even browning.

Step 2: Mash the banana and mix the wet ingredients

In a large mixing bowl, peel and add the banana. Mash it thoroughly with a fork until mostly smooth with just a few small lumps; you should have about 1/2 cup of mashed banana. This banana adds sweetness, moisture, and flavor.

Add the creamy peanut butter, melted and slightly cooled butter, brown sugar, granulated sugar, egg, and vanilla extract. Whisk or stir with a spatula until the mixture is smooth, glossy, and well combined, with no streaks of egg or sugar remaining.

Step 3: Whisk together the dry ingredients

In a separate medium bowl, combine the rolled oats, all-purpose flour, baking soda, ground cinnamon, and salt. Whisk until everything is evenly distributed and there are no clumps of baking soda or flour. This step ensures the leavening and spices are spread evenly throughout the dough so every cookie bakes the same.

Step 4: Combine wet and dry, then fold in mix-ins

Pour the dry ingredients into the bowl with the wet ingredients. Using a spatula or wooden spoon, gently fold everything together just until no streaks of dry flour remain. The dough will be thick and slightly sticky, with visible oats throughout.

If you are using them, fold in the chocolate chips and chopped roasted peanuts until evenly distributed. Avoid overmixing at this stage, which can make the cookies tougher instead of chewy.

Step 5: Scoop and shape the cookies

Using a medium cookie scoop or a measuring spoon, scoop about 1 1/2 tablespoons of dough per cookie and place them on the prepared baking sheets, leaving about 2 inches between each mound to allow for gentle spreading.

Because this dough does not spread as dramatically as some classic cookies, use clean fingers or the back of a spoon to gently press each dough ball down into a thick disc about 1/2 inch thick. This helps them bake evenly and gives a nice, rustic, chewy texture.

Step 6: Bake until set and lightly golden

Place the baking sheets in the oven, one on the upper rack and one on the lower rack. Bake for 10–12 minutes, rotating the pans front to back and swapping racks halfway through baking.

The cookies are done when the edges look set and lightly golden brown, the tops appear dry, and the centers are just barely soft. They will continue to firm up as they cool, so avoid overbaking if you want a chewy texture.

Step 7: Cool and serve

Remove the baking sheets from the oven and let the cookies cool on the trays for about 5 minutes. This resting time allows them to set up, making them easier to move without breaking.

Transfer the cookies to a wire rack to cool completely, or enjoy them slightly warm while the chocolate chips are still melty and the centers are soft. Serve with a glass of cold milk, hot coffee, or tea for the ultimate cozy treat.

Pro Tips

• Use a very ripe banana: The riper the banana (deep yellow with plenty of brown spots), the sweeter and more flavorful your cookies will be.
• Choose the right peanut butter: A standard creamy peanut butter (like classic shelf-stable brands) works best. Natural peanut butters that separate can make the dough too oily or loose unless you stir them extremely well.
• Do not overbake: These cookies should look just set around the edges and slightly soft in the middle when you pull them from the oven. They firm up as they cool, giving you that perfect chewy texture.
• Chill if needed: If your dough seems very soft (especially in a warm kitchen), chill it in the fridge for 20–30 minutes before scooping. This helps the cookies hold their shape.
• Weigh for best results: If you have a kitchen scale, use the gram measurements for consistency and reliably chewy cookies every time.

Variations

• Extra-chunky version: Stir in up to 3/4 cup total of chunky mix-ins such as chocolate chips, chopped peanuts, raisins, or chopped dried banana chips for added texture.
• Gluten-free option: Use certified gluten-free oats and substitute the all-purpose flour with a 1:1 gluten-free baking flour blend. Check all labels to ensure ingredients are gluten-free.
• Spiced breakfast cookies: Increase cinnamon to 1 tsp, add a pinch of nutmeg, and toss in a handful of chopped walnuts or seeds. These make a hearty, just-sweet-enough breakfast-style cookie.

Storage & Make-Ahead

Once completely cooled, store the cookies in an airtight container at room temperature for up to 4 days. For slightly softer cookies, you can place a small piece of bread or a slice of apple in the container (replace it every day or two); the cookies will absorb a bit of the moisture.

To freeze baked cookies, arrange them in a single layer on a tray and freeze until firm, then transfer to a freezer bag or airtight container. They keep well for up to 2 months. Thaw at room temperature or warm briefly in a low oven.

For make-ahead dough, scoop the cookie portions onto a baking sheet, freeze until solid, then store the frozen dough balls in a freezer bag for up to 2 months. Bake from frozen at 350°F (175°C), adding 1–2 extra minutes to the baking time.

Nutrition (per serving)

Approximate values per cookie (1 of 20): about 160 calories, 7–8 g fat, 18 g carbohydrates, 2–3 g protein, and 1–2 g fiber. Actual nutrition will vary based on the specific brands of peanut butter, chocolate chips, and any optional mix-ins you use.