Grease your madeleine tray with a scant amount of unsalted butter. Too much will result in crusty cakes. Place the tray in the fridge while you prepare your batter.
Melt your butter in the microwave, or on the hob using a double-boiler, and set aside to cool slightly while you measure your other ingredients.
If your eggs are not room-temperature, submerge them briefly in slightly warm water. If your eggs are too chilly they will not achieve the volume required. Using a stand mixer, hand mixer or even a whisk if you’re brave, beat the eggs and sugar together until they are very pale and have reached the “ribbon stage”. This will take around five minutes with an electric mixer. At the very end, add in the vanilla and pepper.
Sift together your flour, baking powder and salt, before folding gently into the egg mixture. Use a metal spoon or rubber spatula, knocking as little air as possible out of the eggs. Stir until the flour is just incorporated.
Add a couple of spoonfuls of the egg, sugar and flour mixture into your cooled, but still melted, butter, and stir until mostly-combined. This will make it easier to add the butter to the rest of your mixture and fold until the batter is smooth and silky.
Cover the bowl with cling film and refrigerate for a minimum of one hour, up to overnight. This chilling time is crucial for developing a light, fluffy sponge, preventing crusting and growing a sizeable “hump” on the underside of your madeleines.
Once the batter is thoroughly chilled pre-heat your oven to 175C (170C fan). Retrieve your batter and the tin from the fridge and portion out your cakes. You should have enough batter for 18 standard-sized madeleines or 12 extremely generous ones. The batter will be very stiff, but do not be tempted to smush it about in the tin; it will self-level in the oven and spill neatly into the characteristic ridges.
Bake for 9-12 minutes, depending on your oven. I am guilty of sitting on the oven floor and babysitting my madeleines as they cook, biting my nails as I wait for the batter to bulge into the all-important hump, or belly, which means the batch has succeeded. As soon as the cakes are golden and springy to the touch they are ready to pull out of the oven.
Allow your cakes to cool in the tin for a short while before moving them to a cooling rack, scalloped-side down. While they finish cooling you can melt your white chocolate (if nothing else, to prevent you from snaffling any of the still-warm madeleines. They will smell delicious, and you will want to eat at least four before you’ve finished them off.) You can use a double-boiler on the hob or the microwave on low-power.
Once your chocolate is melted you can choose to drizzle your madeleines for a fun, informal look, but I like to dip mine, like langues des chats. For this, you’ll find a narrow container will give you straighter lines and a deeper well of chocolate to dip into. A pyrex measuring jug is ideal.
Set your chocolate-dipped madeleines hump-side-down on the cooling rack while the chocolate hardens. Once set, eat right away. Freshly-baked madeleines do not keep well, especially if they are on the smaller side. If you really must keep them overnight, store them in an airtight container in the fridge and allow them to come back to room temperature before eating.