Whisk together water and yeast in the bowl of a stand up mixer; let sit until yeast is foamy, about 10 minutes. Add flour, salt, and stir with a fork until dough forms and all flour is absorbed; let dough sit to allow flour to hydrate, about 20 minutes. Attach the dough hook to your mixer begin to mix the dough. Continue to knead until smooth and elastic, about 10 minutes.

Spray a large bowl with the vegetable spray and transfer the dough ball to it. Cover the bowl with plastic wrap (we use a shower cap -- the kind you get in the hotels, they work perfectly) and place bowl in a cold oven.

Let dough rest until doubled in size, about 45 minutes.

Transer dough to a lightly floured work surface, and shape into an 8" x 6" rectangle. Fold the 8" sides toward the middle, then fold the shorter sides toward the center, like a T-shirt. Return the dough, seam side down, to the greased bowl. Cover with plastic again, and return to oven. Let sit until doubled in size, about 1 hour.

Remove the bowl with dough from oven, and place a cast-iron skillet or heavy pan on the bottom rack of your oven; position another rack above the skillet/pan, and place a baking stone or upside down rimless sheet pan on it.

Heat oven to 475 F. Transfer dough to a lightly floured work surface, and cut into three equal pieces; shape each piece into a 14-inch-rope. Flour a sheet of parchment paper on a rimless baking sheet; place ropes, evenly spaced, on paper. Lift paper between ropes to form pleats; place two tightly rolled kitchen towels under long edges of paper, creating supports for the loaves. Cover loosely with plastic wrap; let sit until they double in size, about 50 minutes.

Uncover; remove towels, and flatten paper to space out loaves. Using a sharp razor, knife, bread lame, or scissors, slash the top of each baguette at a 30-degree angle in four spots; each slash should be about 4 inches long. Pull out the oven rack with the stone or baking sheet on it and, using the corner of the parchment paper as a guide, slide the loaves, still on the parchment paper, onto the baking stone or pan.

Place ice cubes in the skillet or pan (this produces steam that lets the loaves rise fully before a crust forms.)

Bake the baguettes until darkly browned and crisp, 20 to 30 minutes; cool before serving.