Stir together flours,salt and yeast in medium bowl. Add 3/4 cup water and stir until ingredients come together into a coarse ball. Add flour or water a tablespoon at a time only if necessary. Dough should be well hydrated but not too sticky or too stiff.

Sprinkle flour on the counter and knead dough for 4-6 minutes. Or knead in mixing bowl on medium speed with dough hook for about 4 minutes.

Place dough in a lightly oiled bowl and roll it around to fully coat it. Cover with plastic wrap and let rest a room temperature for 1 hour or until 1 1/2 times it's original size.

Remove from the bowl. Lightly knead it to degas it slightly and place back in the bowl. Cover with plastic. Place in refrigerator overnight. Keeps in fridge for up to 3 days or freeze in airtight plastic bag for up to 3 months.

Take starter from refrigerator 1 hour before making the dough. Cut into 10 small pieces with a pastry scraper or serrated knife. Cover with plastic wrap or a towel and allow to sit at room temperature for 1 hour.

Stir together all purpose flour,bread flour, salt, yeast and starter dough in a medium bowl or using the bowl of an electric mixer. Add the water and stir until everything comes together. Add water or flour as needed so you have dough that is not too sticky or stiff.

Knead dough on medium speed using an electric mixer for about 6 minutes. Or place dough on a lightly floured counter and knead by hand for about 10 minutes. Dough should be soft and supple but not sticky. The dough should be able to be easily stretched and temperature about 77 -81 degrees. Knead for a few extra minutes to increase temperature of dough if needed. Lightly oil a large bowl and place dough in bowl. Roll around to coat it with oil. Cover with plastic wrap.

Let sit at room temperature for about 2 hours or until doubled in size. If double before the 2 hours, knead it lightly to degas it and cover and let it rise again.

Remove the dough gently from the bowl and transfer to a lightly floured counter. Cut into 3 equal pieces. Being careful to degas the dough as little as possible. (We want to keep the air bubbles in the bread this creates the beautiful open crumb we adore.)

Gather dough into a rough ball. Stretch the outside of dough underneath being careful not to degas the dough. Continue stretching dough bringing opposite sides together to make a ball. Let loaves relax for a few minutes. Lift dough and gently pull, tugging on opposite ends. We want loaves that are about 8-12 inches in length. Remove they will expand in size and we will need them to fit in our standard size oven.

Crease dough down the center and fold it like a letter. Seal the crease against the counter to create surface tension. Working from the center of the loaf to the outsides gently rock dough to lengthen to desired size. If dough is springing back quickly. Let rest for a few minutes and try again. Place baguettes lightly sprayed parchment that is sprinkled generously with cornmeal.

Let sit at room temperature for 45 to 75 minutes or until loaves are about 1 1/2 times original size. If you poke with your finger that should slightly spring back

Meanwhile prepare oven. Place an empty heavy duty sheet pan or cast iron frying pan on the bottom of the oven (Do not use anything glass). Place a cast iron or baking stone on the center rack. Preheat oven to 500 degrees. Also prepare a water bottle for misting (just a cheap one from the dollar store works fine.) And simmer a few cups of hot water on the stove for later.

Score the top of the loaves by slashing across the top diagonally several times on each loaf. Use a lame or a serrated bread knife.

Using a pizza peel or the back of a sheet pan sprinkle very generously with cornmeal or semolina flour. (This will allow the loaves to slide easily into the oven.)

Open oven. Lay a towel over oven door glass. Transfer baguettes to baking stone in oven. Pour 1 cup hot water into steam pan. Remove towel, close oven door. After 30 seconds,open oven and spray oven walls with water and close door. Repeat 2 more times after 30 second intervals. Then lower oven temperature to 450 degrees. Bake for 10 minutes. Rotate loaves if needed and bake until golden brown. Loaves should be at least 205 degrees in center. This will take about an additional 10-20 minutes. If they darken too quickly turn oven down to 350 degrees and bake for an additional 5 to 10 minutes.

Remove loaves and cool on rack for at least 40 minutes before slicing and serving.