Banana Bread — The Science of Moisture

Ingredients

• 340 g overripe bananas, mashed; 3 large, skins 80–90% brown-to-black
• 100 g unsalted butter, browned until milk solids are hazelnut-coloured, then cooled to room temperature
• 100 g light brown sugar
• 50 g granulated sugar
• 1 large egg
• 5 ml vanilla extract
• 190 g all-purpose flour, spooned into measure and levelled, or weighed; 10–12% protein
• 5 g baking soda
• 3 g fine salt
• To finish
• 1 tsp flaky salt (e.g. Maldon), pressed into the top of the batter before baking
• For the pan
• 15 g unsalted butter, softened, for greasing
• 10 g all-purpose flour, for dusting the greased pan

Method

1. 1
   If bananas are under-ripe, place them unpeeled on a baking sheet and roast at 150 °C for 15–20 minutes, until the skins are uniformly blackened. Allow to cool before peeling. This accelerates enzymatic browning and concentrates sweetness; it does not fully replicate natural ripening. Verify ripeness by smell: the aroma must be intensely fruity with the characteristic isoamyl-acetate note of ripe banana.
2. 2
   Brown the butter. Melt 100 g unsalted butter in a light-coloured saucepan over medium heat, swirling occasionally. It will foam; when the foam subsides, watch for golden-brown flecks on the pan floor. The aroma shifts from dairy to hazelnut. Remove from heat immediately and transfer to a bowl. Cool to room temperature before proceeding.
3. 3
   Heat the oven to 175 °C. Butter and flour the 23 × 13 cm loaf pan, tapping out any excess flour.
4. 4
   Mash the bananas thoroughly with a fork in a large bowl until no large lumps remain. Add the cooled browned butter, 100 g light brown sugar, 50 g granulated sugar, the egg, and vanilla extract. Stir to combine. The mixture should be uniformly loose and liquid.
5. 5
   This is where the dish lives or dies. Add the flour, baking soda, and fine salt directly to the wet mixture. Fold with a spatula in 20–30 gentle strokes until the flour just disappears. Visible streaks of flour are preferable to one stroke too many. The batter is very wet; overworking develops gluten and produces a dense, gummy loaf rather than a tender one. Do not use a stand mixer. Transfer to the oven within minutes of mixing — the baking-soda reaction with the bananas' natural acidity begins immediately.
6. 6
   Pour the batter into the prepared pan. Press flaky salt evenly across the surface. Place in the oven. Do not open the door during the first 30 minutes. If the top browns too quickly after 40 minutes, tent loosely with aluminium foil.
7. 7
   Bake for 55–65 minutes. Insert a skewer into the centre: it should emerge with moist crumbs clinging to it — not wet batter, and not clean. A clean skewer indicates an overbaked loaf. The top should be domed and crackled, with a deep mahogany crust.
8. 8
   Remove from the oven. Tap the top of the loaf gently — it should sound hollow, not dull. Press the centre lightly; it should spring back slowly over approximately two seconds, leaving a faint impression that fills in. Cool in the pan for 20 minutes minimum, ideally one hour, before slicing. Cutting the loaf hot releases steam and produces a gummy slice.