Total time: 16-18 hours including just 25 minutes of active work, plus 20-30 minutes baking time.
Mix the preferment as follows: 50g flour blend 50g warm water 15g levain or yogurt. Loosely cover with a damp kitchen towel and leave in warm place for 12 hours. (At night before bed works great. If it's cold outside, you can put in an oven that's been heated up and then turned off.)
2) MIX THE DOUGH
Add the following to the preferment:-remaining flour blend-350g warm water-10g salt-3g active dry yeast (This is needed only if using a yogurt preferment, but can be omitted if using a levain preferment. If you use levain and omit the commercial yeast, you’ll need to double the bulk fermentation time.) Mix together to form a homogenous, wet dough.
3) BULK FERMENT
Scrape into a lightly oiled bowl and let sit to bulk ferment, loosely covered, for an hour. Stretch each side of the dough up and fold over the rest of the dough in turn. Let sit for another hour.
4) BAGUETTE PRE-SHAPE
Lightly flour a work surface and place the dough on the surface. Divide the dough in two equal pieces, about 450g each, to make 2 baguette shapes. Roll each piece of dough into a football shaped pre-shape and let sit on a lightly floured surface, seam side down, for 20 minutes to rest, covered with a kitchen towel.
5) SHAPE AND PROOF
Take each piece and flip onto a lightly floured surface so that the seam is now on top. Stretch out sideways into a rectangular mass, about 6-7 inches wide, and then fold the bottom third up towards the center of the rectangle. Now fold the top third down towards the center of the rectangle and lightly pat down to seal. Next, fold the top edge of the dough down to meet the bottom edge and seal together to form a tube of dough. Roll the tube out to desired length (~12" recommended for a nice crust to crumb ratio), and taper at the ends. Place the baguette between the folds of a kitchen towel or a linen proofing cloth, seam side down. Let rise, covered with a second kitchen towel, for about 30-60 minutes, until the baguette feels fluffy and a dent created by pushing your finger into the surface remains in place and doesn't immediately spring back.It should not have doubled in size.
Preheat your oven to 450 degrees Fahrenheit (with a baking stone if you have one). Once preheated, transfer the baguettes, maintaining seam side down, onto the baking surface (stone, baking pan, etc.). Cut three slashes up the length of the baguette on an angle, with about 1/4 inch between the cuts. The second and third cuts should begin below the end section of the one before it. Bake for 20-25 minutes until golden brown. Test for doneness by tapping the bottom of the baguette - it should sound hollow. When done, cool on a cooling rack completely before enjoying. We recommend enjoying it dipped in olive our or with a spread of chevre.
Note: Dough can be formed into one large ~900g boule instead of two baguettes. Baking time might need to be increased slightly to account for the larger mass of dough.