Ingredients
Equipment
Method
- Position the oven rack in the middle position. Preheat the oven to 350°F (175°C). Line two light-colored aluminum baking sheets with parchment paper and set aside.
- Peel the 2 medium ripe bananas and place them in a medium bowl. Mash with a fork in a pressing and smearing motion for 60 to 90 seconds until smooth with no chunks larger than a small pea. Set aside.
- In a large mixing bowl, combine the ½ cup (113g) melted cooled butter, ½ cup (100g) packed light brown sugar, and mashed banana. Stir with a silicone spatula in wide circular strokes for 20 to 25 strokes until fully combined with no butter streaks.
- Add the 1 large room temperature egg and 1 teaspoon (5ml) pure vanilla extract. Stir for 15 to 20 strokes until the egg is fully incorporated and the mixture looks smooth and slightly thickened with no egg streaks visible.
- Add the ½ teaspoon (2g) baking soda, ½ teaspoon (1.5g) ground cinnamon, and ¼ teaspoon (1.5g) fine sea salt directly to the wet mixture. Stir with 5 to 6 short strokes to distribute evenly.
- Add the 1 cup (120g) spooned and leveled all-purpose flour followed by the 1½ cups (135g) old-fashioned rolled oats on top. Fold from the bottom of the bowl upward in slow deliberate strokes — approximately 15 to 18 strokes — until no dry flour streaks remain and the oats are evenly distributed. Do not overmix.
- Using a 2-tablespoon cookie scoop, portion the dough onto the prepared baking sheets, spacing each portion at least 2 inches (5cm) apart. Each portion should weigh approximately 45g. This recipe yields exactly 18 cookies. Do not press the mounds flat before baking.
- Bake at 350°F (175°C) for 11 to 13 minutes until the edges look set and lightly golden and the centers still look slightly underdone. Do not wait for the centers to look fully set before pulling the pan.
- Leave the cookies on the hot baking sheet for exactly 5 minutes — do not move them. Transfer to a wire cooling rack and cool for a minimum of 10 minutes before eating.
Notes
Banana: peel must be 70%+ brown-spotted; fully blackened wet bananas carry excess moisture and cause flat cookies
Old-fashioned rolled oats only: quick oats produce a smooth, cakey cookie with no visible oat texture
Butter: melted and cooled to room temperature before mixing — warm butter causes excessive spread
Egg: must be at room temperature — cold egg causes butter to seize into greasy streaks
Flour: weigh at 120g or spoon and level — scooping directly packs in 20–30% extra flour
Baking soda: test freshness before starting — drop ½ tsp into 3 tbsp hot water, should bubble vigorously
Storage: lidded hard-sided container, parchment between layers, room temperature up to 4 days
Freeze baked: wrap individually in plastic wrap, then zip-lock bag, up to 2 months
Freeze unbaked: freeze portioned mounds solid, bake from frozen at 350°F (175°C) for 14–16 minutes
Make-ahead: baked cookies better on Day 2 — banana flavor deepens overnight
Scaling: doubles reliably — do not scale baking soda linearly beyond double; triple batch use 1¼ tsp total
High altitude above 3,500ft: reduce baking soda to ¼ tsp, add 2 tbsp flour, raise oven to 375°F (190°C)
High humidity: add 1 tbsp (8g) extra flour if dough mounds are not holding shape on the pan
Allergens: contains gluten (flour, oats), dairy (butter), eggs