Prepare the tin and oven – Grease the loaf tin thoroughly and line it with baking parchment, leaving an overhang for easy lifting. Preheat the oven so the temperature is stable before baking.

Cream butter and sugar – Beat the softened butter and caster sugar until pale and fluffy. This step adds air and helps prevent a dense loaf.

Add the eggs gradually – Beat in the eggs one at a time, mixing well after each addition to keep the batter smooth.

Mix in bananas and vanilla – Stir in the mashed bananas and vanilla extract until evenly combined. The mixture will look loose, which is normal.

Combine dry ingredients – In a separate bowl, mix the self-raising flour, cocoa powder, and baking powder so the cocoa is evenly distributed.

Bring the batter together – Fold the dry ingredients into the wet mixture with the milk. Mix gently and stop as soon as the batter is smooth.

Add chocolate chips – Fold in the chocolate chips, spreading them evenly without overmixing.

Bake until set – Spoon the batter into the tin, level the top, and bake until risen, firm, and a skewer inserted into the centre comes out clean.

Cool fully before slicing – Leave the loaf in the tin briefly, then lift out and cool completely on a wire rack so it slices neatly.