Step 1

In a large bowl, mix together the bread flour, all-purpose flour, salt and yeast.

Step 2

Stir in the water until a loose, shaggy dough has formed. Cover with plastic wrap and let rise at room temperature for a minimum of 12 hours but up to 18 hours. (After the 18 hours you can use it or put it in the fridge for up to 2 days)

Step 3

Butter a 9x5-inch (23x12½ cm) loaf pan. Set aside.

Step 4

Knock the air out of the dough and transfer to a floured surface.

Step 5

Shape into an 8x12-inch (20x30 cm) rectangle. Starting at an 8-inch (20 cm) edge, fold in thirds like a letter, then place, seam side down into the prepared loaf pan.

Step 6

Cover and let rise until doubled in size, about 1 ½ - 2 hours. Towards the end of the rise time, preheat the oven to 450°F (230°C).

Step 7

Dust the loaf with a bit of flour and score down the center with a sharp knife.

Step 8

Bake for 35-40 minutes, until the top of the loaf is a deep golden brown.

Step 9

Let cool completely before slicing. Store the bread in an airtight container at room temperature for up to 4 days. It also can be sliced and frozen.