The vintage Pyrex #441 bowl is my favorite bowl to bake the peasant bread in — the perfectly round shape of the bowl creates a beautiful round loaf. It belongs to a set of four nesting bowls (also called Cinderella bowls, specifically the Pyrex #441, #442, #443, #444), which I have purchased from Ebay. I absolutely love the set in general, but I love most of all that I can bake the whole batch of peasant bread in the second largest bowl (#443) and half of the batch in the smallest bowl (#441). The set runs anywhere from $35 to $50 or higher depending on the pattern of the Pyrex. More pictures of the bowls can be found on this post.
This is a sticky, no-knead dough, so, some sort of baking vessel, such as pyrex bowls (about 1-L or 1-qt) or ramekins for mini loaves is required to bake this bread. You can use a bowl that is about 2 qt or 2 L in size to bake off the whole batch of dough (versus splitting the dough in half) but do not use this size for baking half of the dough — it is too big.
I buy SAF Instant Yeast in bulk from Amazon I store it in my fridge or freezer, and it lasts forever. If you are using the packets of yeast (the kind that come in the 3-fold packets), just go ahead and use a whole packet — It's 2.25 teaspoons. I have made the bread with active dry, rapid rise, and instant yeast, and all varieties work. If you are interested in buying yeast in bulk, here you go: SAF instant yeast and Red Star Baking Yeast (use this if you prefer to stick to active-dry, though I highly recommend using instant). The beauty of instant yeast is that there is no need to do the proofing step — you can add the yeast directly to the flour. I never use active-dry yeast anymore.
Several commenters have had trouble with the second rise, and this seems to be caused by the shape of the bowl they are letting the dough rise in the second time around. Two hours for the second rise is too long. If you don't have a 1-qt bowl, bake 3/4 of the dough in a loaf pan and bake the rest off in muffin tins or a popover pan — I recently made 6 mini loaves in a popover pan. The second rise should take no more than 30 minutes.
Also, you can use as many as 3 cups of whole wheat flour, but the texture changes considerably. I suggest trying with all all-purpose or bread flour to start and once you get the hang of it, start trying various combinations of whole wheat flour and/or other flours. Also, measure scant cups of flour if you are not measuring by weight: scoop flour into the measuring cup using a separate spoon or measuring cup; level off with a knife. The flour should be below the rim of the measuring cup.
#1. Cornmeal. Substitute 1 cup of the flour with 1 cup of cornmeal. Proceed with the recipe as directed.
#2. Faux focaccia. Instead of spreading butter in two Pyrex bowls in preparation for baking, butter one 9x9-inch glass baking dish and one Pyrex bowl or just butter one large 9x13-inch Pyrex baking dish. If using two vessels, divide the dough in half and place each half in prepared baking pan. If using only one large baking dish, place all of the dough in the dish. Drizzle dough with 1 tablespoon of olive oil (if using the small square pan) and 2 tablespoons of olive oil (if using the large one). Using your fingers, gently spread the dough out so that it fits the shape of the pan. Use your fingers to create dimples in the surface of the dough. Sprinkle surface with chopped rosemary and sea salt. Let rise for 20 to 30 minutes. Bake for 15 minutes at 425ºF and 17 minutes (or longer) at 375ºF. Remove from pan and let cool on cooling rack.