Preheat the oven to 180°C and line a baking tray with parchment paper to ensure even baking and prevent sticking.
Mix oats, flour, baking soda, baking powder, spices, and salt in a bowl until evenly combined for consistent flavor.
Whisk pumpkin purée, butter, sugars, egg, and vanilla until smooth to create a balanced wet mixture.
Combine wet and dry ingredients gently, mixing just until incorporated to maintain a soft texture.
Scoop and shape cookies onto the tray, flattening slightly for even baking and proper texture.
Bake for 12–15 minutes until edges are set and centers remain soft, then cool before serving.