Preheat the oven to 160°C fan / 180°C non-fan (320°F fan / 350°F non-fan) and line a baking tray with baking paper.
Mix the butter, sugar, treacle/molasses (if using) and aquafaba in a bowl until smooth and lump-free. The mix may look curdled, this is fine.
100 g (7 tbsp) vegan block butter*, 150 g (3/4 cup) granulated sugar or caster sugar, 1 tsp treacle or molasses*, 60 ml (4 tbsp) aquafaba*
Add the flour, cinnamon, baking powder and salt and stir together.
75 g (1/2 cup + 2 tbsp) plain white flour, 1 tsp ground cinnamon, 1/2 tsp baking powder, pinch fine table salt
Add the oats, raisins and nuts (or whatever mix-ins you're using). Mix together until fully combined.
140 g oats, 60 g raisins, dried fruit or vegan chocolate chips, 40 g chopped nuts, seeds or desiccated coconut
Roll heaped teaspoons of dough into balls and place onto the lined tray, spacing them a few centimetres apart as they will spread. Flatten slightly and then bake for 8-12 minutes, until the edges are set and browned. They will crisp up as they cool.
Transfer to a wire rack to cool completely then place into an airtight container at room temp. They will keep for up to 2 weeks.