Mash the banana really well in a large bowl.
460 g banana (peeled weight)*
Whisk in the oil, yogurt, sugar, vinegar and vanilla extract.
180 ml (¾ cup) neutral oil (I use olive), 90 g (6 Tablespoons) vegan Greek style yogurt, 250 g (1 ¼ cups) light brown soft sugar, 2 teaspoons vinegar, 2 teaspoons vanilla extract
Whisk in the baking powder, bicarbonate of soda, cinnamon, nutmeg and salt, followed by the flour. Be careful not to over-beat the batter, just mix it until no streaks of flour remain.
2 teaspoons baking powder, 1 ½ teaspoons bicarbonate of soda (baking soda), 2 teaspoons ground cinnamon, ½ teaspoon ground nutmeg, ½ teaspoon salt, 420 g (3 ½ cups) plain (all-purpose) flour
Gently fold in the chocolate chips.
200 g (7 oz) vegan chocolate chips
Cover the bowl with a tea towel and let it rest for 15 minutes. Meanwhile, preheat the oven to 220°C/200°C fan/425°F/gas mark 7. Line two 12 hole mufin tins with 10 cases, spreading them out across the tins so that there is a gap in between each one.
Divide the batter between the muffin cases, filling them all the way to the top; they should be almost overflowing. An ice cream scoop is handy for this.
Bake for seven minutes then turn the oven down to 180°C/160°C fan/350°F/gas mark 4. Bake for a further 15-18 minutes, until a skewer inserted into the centre comes out clean.
Allow the muffins to cool in the tin for 5 minutes, then transfer them to a wire rack and leave to cool completely. Once cold store in an airtight container.