Mash the bananas thoroughly in a mixing bowl.
Add the oats, lemon zest, lemon juice, poppy seeds and vanilla extract. Mix well to combine.
Leave the mixture to rest for 5 minutes so the oats can absorb some of the moisture.
If the mixture seems too thick, add a splash of plant-based milk. If it feels too wet to shape, stir in a little extra oats.
Divide the mixture into portions and shape into balls, then flatten slightly between your palms to form cookies.
Air Fryer Method: arrange the cookies in the air fryer basket, leaving a little space between them. Air fry at 180°C for 12–15 minutes, turning once halfway through cooking.
Oven Method: preheat the oven to 180°C and line a baking tray with baking parchment. Arrange the cookies on the tray and bake for 15–18 minutes, or until lightly golden.
Allow the cookies to cool slightly before serving.
Store in an airtight container for up to 3 days. They can also be frozen and thawed as needed.