Preheat and prepare: Set your oven to 200°C (180°C fan) and line a 12-hole muffin tin with paper cases. The paper should stand slightly proud of the tin edges — this helps the muffins rise into tall, elegant domes rather than squat discs.

Whisk the dry ingredients: In a medium bowl, combine the flour, baking powder, bicarbonate of soda, and salt. Whisk vigorously for about 15 seconds until the mixture looks pale and feels light as sand. This aerates the flour and distributes the leaveners evenly.

Cream the butter and sugar: In a large mixing bowl, beat the softened butter and golden caster sugar together with a hand mixer or stand mixer on medium speed for 3–4 minutes. You’re looking for a pale, fluffy mass that smells sweetly of caramel — the mixture should feel airy and look almost like whipped frosting.

Add the wet ingredients: Beat in the eggs one at a time, scraping down the sides after each addition. The batter should look smooth and glossy, with no streaks of egg white visible. Stir in the vanilla extract, then fold through the mashed banana and yoghurt. The mixture will look slightly curdled at this stage — do not worry, that is exactly right and will resolve once you add the flour.

Fold the dry ingredients: Gently fold the flour mixture into the wet batter using a rubber spatula. Stop as soon as you see the last streak of flour disappear — about 10 to 12 folds. You should feel the batter thicken beneath the spatula, and it will look lumpy and slightly under-mixed. Overworking now will make the muffins dense and tough.

Add the chocolate chips: Fold in 120 g of the chocolate chips with just 3 or 4 turns of the spatula. The batter should be studded with dark flecks, and you should hear a soft clatter as the chips tumble through the mixture.

Rest the batter: Cover the bowl with a clean tea towel and let it sit at room temperature for 15 minutes. During this time, the starches in the flour absorb moisture and the gluten relaxes. The batter will visibly thicken and become slightly tacky — this is what produces that domed top and tender crumb.

Fill the cases: Divide the batter evenly among the 12 paper cases, filling each until the batter is level with the top edge of the paper. Use two spoons or a spring-loaded ice cream scoop for neatness. Press the reserved 30 g of chocolate chips into the tops of the batter, pushing them just below the surface so they remain visible as they melt.

Bake to perfection: Place the tin on the middle rack and bake for 5 minutes at 200°C, then reduce the temperature to 180°C (160°C fan) without opening the door. Bake for a further 15–17 minutes. The muffins are ready when the tops are deep golden brown, spring back firmly when touched, and a skewer inserted into the centre comes out with just a few moist crumbs attached. The kitchen will smell intensely of caramelised banana and toasted butter.

Cool and present: Let the muffins rest in the tin for 5 minutes, then transfer them to a wire cooling rack. The paper cases should peel away easily once cooled. For a restaurant-style finish, cool completely, then dust lightly with icing sugar through a fine sieve and serve on a wooden board or a slate tile.