3 1/2 cups bread flour
3 T whole wheat flour
2 1/4 t salt
4 t active dry yeast
1/2 c sourdough starter
1 1/4 c water
In a large bowl or Kitchen Aid, mix the flours and the salt thoroughly. Sprinkle in the dry yeast. Add the sourdough starter. Begin mixing the dough. Slowly trickle in the water while mixing the dough in the kitchen aid with a dough hook, or with your hands. Slightly more or less water may be required to get the dough to the proper consistency. More water makes the dough stickier, but softer and easier to work with. Continue mixing and adding water until the dough forms a ball. Mix the dough for three or four minutes.
Remove the dough from the mixing bowl and place it on a floured surface for kneading. Allow the dough to sit for two minutes. Knead the dough by pressing it flat, folding it in half, pressing it flat again, rotating it 90˚ and repeating. You will want to knead the dough for at least ten minutes.
Sprinkle flour in the bottom of a bowl that is large enough for the dough to double in size. Flour the ball of dough and place it in the bowl. Cover the bowl with plastic wrap or a damp cloth. Place the bowl of dough in a slightly warmed oven and let rise for 25 minutes.
Remove the dough from the bowl and place it on a floured surface. Press the dough into a circle that is about half an inch thick. Fold the right third of the circle of dough over the middle and then fold the left third of the dough over that. Rotate the dough 90˚ and press it back down to about 1/2 inch thick. Repeat the process of folding the dough in thirds, left and right.
Cut the ball of dough in half. Put one half of the dough aside and cover with a damp cloth. Flatten the other half of the dough into a rectangle, about 3/4 of an inch thick. Press a trench with the side of your hand in the middle of the dough parallel to the longest side. Fold the dough in half along that trench, pressing the two edges of dough together to seal it. Place the dough crease down, and flatten it into another rectangle. Turn it over and form another trench on the original crease. Fold the dough in half again, and seal the edges. Roll the dough out to be slightly less than the length of your baguette pan. Place the dough in a lightly oiled baguette pan (or on a cookie sheet), crease-side down. Repeat the loaf-forming process with the second half of the dough and place it in the other half of your baguette pan (or on the same cookie sheet).
Place a damp cloth over the loaves and allow them to rise for about an hour, ideally in a slightly warm oven. Place a cookie sheet that contains at least two cups of water on the bottom rack of your oven and preheat the oven to 450˚ so that it is at that temperature when loaves have risen for an hour.
With a very sharp knife or a pair of cooking scissors, cut diagonal slices in the top of the dough, about 1/3 of an inch deep. Exactly how you cut your dough (at what angle and how many cuts) is very much a personal preference kind of thing. However, the cuts should be greater than 45˚ running along the length of the dough. Sprinkle water on the surface of the loaves and put it in the oven on the middle rack.
Bake the bread for 16 minutes. Reduce the temperature of the oven to 375˚ and bake the bread for an additional 7 minutes.