3tablespoons(1.5 ounces) extra-virgin olive oil, plus extra for brushing
¼cup(0.55 ounces) fresh thyme leaves, chopped(alternatively use rosemary leaves, as original recipe does)
3cups(15.3 ounces) unbleached all-purpose flour
½cup(2.8 ounces) whole-wheat flour
1tablespoon plus 2 teaspoons(0.56 ounces) kosher salt
Combine very warm water and yeast in a large bowl. Stir with a fork until yeast dissolves. Let stand 3 minutes, then add the poolish, cool water, olive oil, and thyme. Combine with your fingers for about 2 minutes, breaking up sponge until yeast mixture looks milky and slightly foamy.
Add flours and salt. Mix with your fingers to incorporate, scraping the bowl’s sides and folding dough over itself until it gathers into a mass. When sticky strands of dough cling to your fingers, gather it into a ball and move it to a lightly floured surface. If dough is very firm, add 1 tablespoon water.
Knead dough for about 5 minutes, until it becomes smoother and supple. Put the dough back into the mixing bowl, cover it with oiled plastic wrap and let it rest for 20 minutes to smooth out and develop elasticity.
Return the dough to the lightly floured survace and knead for 2 to 3 minutes, until smooth and stretchy. Do not knead extra flour into the dough. It should be soft and loose.
Place the dough in a lightly oiled bowl. Cover the dough with oiled plastic wrap and allow it to rise at room temperature (75 to 78°F) for 1 hour. After one hour, turn the dough while it is still in the mixing bowl. Gently deflate the dough in the middle of the bowl with your fingertips, then fold the left side over the middle, and the right side over the middle. Fold the dough in half, gently pat it down, and then turn it over so the seam is underneath. Cover the dough tightly with plastic wrap or a large plastic bag, and place in the refrigerator to chill for at least 8 hours or overnight.
Remove from refrigerator and let warm until it begins to rise again, 1 ½ to 2 hours.
Cover a peel or the back of a sheet pan with parchment paper, then sprinkle with cornmeal. Place dough, which may be quite sticky, on a well-floured surface and divide it into 2 equal pieces. Shape each into a boule, or round loaf. Flour the seam of each and place loaves, seam side down, on peel or pan, leaving 3 to 4 inches between them for rising and spreading. Cover with oiled plastic wrap and let rise for 1 ¼ to 1 ¾ hours, or until loaves have doubled in bulk.
Thirty minutes before baking, preheat oven to 450°F. Fill a plastic spray bottle with water and place a small pan (such as a mini loaf pan) on the lowest possible rack of the electric oven. Also place a cast-iron pan (that you are willing to get rusty) next to the small pan (I just used another small pan), fill a teakettle with water to be boiled later, and have a metal 1-cup measure with a straight handle available near the kettle.
Five to 10 minutes before the loaves are ready to bake, carefully place 2 or 3 ice cubes in the small pan in the bottom of the oven. This helps to create moisture in the oven prior to baking. If using a water pan, also turn the water on to boil.
Mist the tops of the loaves with water, then using a razor blade, cut a shallow tick-tack-toe pattern on top of each loaf, being careful not to tear dough. Gently slide loaves from the parchment onto the baking stone (if you’re baking with a stone simply slide the sheet pan onto the empty oven rack). Pour 1 cup of boiling water into the cast-iron pan and immediately shut oven door. After about 1 minute, quickly mist loaves with water 6 to 8 times, then shut the oven door.
Bake for 20 minutes, then reduce oven temperature to 400°F and bake 10 to 15 minutes longer, until loaves are light golden brown and sound hollow when tapped on the bottom. Brush loaves with olive oil using a pastry brush. Cool on a rack.