- 325 g (2 1/2 cups) plain flour
- 1 1/2 tsp baking powder
- 1 tsp bicarbonate of soda
- 1 pinch salt
- 150 g (2/3 cup) unsalted butter, softened
- 125 g (1/2 cup) golden caster sugar
- 2 large eggs
- 3 tbs milk
- 1 tsp vanilla extract
- 4 medium bananas, very ripe, mashed
- 100 g (2/3 cup) chia seeds
- 140 g (1 cup) walnut halves, divided
Preheat the oven to 180°C (160° fan). Grease and line the base and sides of a 900g loaf tin with greaseproof paper.
Combine the flour, baking powder, bicarbonate of soda, and salt in a large mixing bowl, stirring well.
Beat together the butter and sugar in a separate mixing bowl until pale and creamy, 2 minutes. Beat in the eggs, one by one, and then the milk, vanilla extract, and mashed bananas.
Add the chia seeds and half the walnuts to the dry ingredients, and then stir that mixture into the banana mixture in two additions, stirring until a rough batter forms; take care not to overmix, it shouldn’t be totally smooth.
Spoon the batter into the prepared tin and rap on a work surface to help release any trapped air bubbles. Top with the remaining walnut halves, arranging in two rows spaced apart.
Bake for about 65-75 minutes until golden and risen on top; a cake tester should come out clean from its centre when ready.
Remove from the oven and leave to cool on a wire rack before turning out, slicing, and serving.