Preferment:
1 cup all-purpose flour
1 cup bread flour
1/2 teaspoon salt
1/2 teaspoon instant yeast
2/3 cup warm water
1. In a large bowl, sift together flours and salt. In a small bowl, dissolve yeast in water. Add to flour mixture and stir until dough forms. Let rest 10 minutes.
2. On a floured surface, knead dough briefly, then return to a greased bowl and allow to rise 1 hour at room temperature. Cover bowl with plastic wrap and refrigerate overnight.
Cottage loaf:
All of the preferment
1 teaspoon instant yeast
2/3 cup warm water
1 3/4 cups bread flour
1/4 cup rye flour
1/2 teaspoon salt
1. Remove the preferment from the refrigerator, cut into 8 wedges, and let sit 1 hour until it reaches room temperature.
2. In a small bowl, dissolve yeast in water. In a large bowl, mix together preferment, dissolved yeast, flours, and salt until a rough dough forms. On a floured surface, knead dough 10 to 15 minutes until smooth and elastic. Place in a greased bowl and let sit in a warm place 30 minutes, or until it has doubled in size.
3. Divide dough into 2 pieces (with 1/3 and 2/3 of the dough respectively) and form into tight balls. Place rounds on a greased baking sheet and set 10 minutes.
4. Preheat oven to 425°F. Place the smaller round on top of the larger round. Push a floured chopstick (or wooden spoon handle) completely through the center of the top round and 2/3 of the way into the bottom rounds to join them. Slash both rounds.
5. Bake 40 to 45 minutes, or until golden brown and loaf makes a hollow sound when tapped on the bottom.