Combine Dry Ingredients: In a large mixing bowl, whisk together the 400g of strong white bread flour, 1 ½ tsp of fine sea salt, and ¼ tsp of fast-action yeast. Make sure the salt and yeast are evenly distributed.

Add Water and Mix: Pour in the 300ml of tepid water. Use a spatula or wooden spoon to mix everything together until just combined. The dough will be very sticky and shaggy – this is exactly what you want. Don't be tempted to knead it.

The First Rise: Cover the bowl with cling film or a clean tea towel. Leave it on your worktop at room temperature for 12 to 18 hours. After this time, the dough will have doubled in size and be covered in bubbles.

Shape the Dough: Generously flour a clean work surface. Scrape the sticky dough out of the bowl and onto the flour. Sprinkle a little more flour on top. Gently fold the dough over on itself two or three times to form a rough ball. There's no need to be aggressive here.

The Second Rise: Place the dough on a piece of baking parchment. Cover it loosely with cling film or a tea towel and let it rest for 30 minutes.

Preheat the Oven: While the dough is having its final rest, place a cast iron Dutch oven (with its lid on) into your oven. Preheat the oven to 230°C (210°C fan). What works best for me is letting the Dutch oven heat up for the full 30 minutes to ensure it's searingly hot.

Bake with the Lid On: Carefully remove the hot Dutch oven from the oven. Using the baking parchment as a sling, lower your dough into the pot. Be very careful as the pot will be extremely hot. Put the lid back on and return it to the oven. Bake for 30 minutes.

Bake with the Lid Off: After 30 minutes, carefully remove the lid. The bread will be pale but well-risen. Continue to bake for another 15-20 minutes, or until the crust is a deep, golden brown and looks beautifully crisp.

Cool Completely: Carefully lift the bread out of the Dutch oven and place it on a wire rack to cool completely. This step is crucial! It allows the crumb to set properly. Resist the urge to slice into it for at least an hour.