• In a large bowl, mix the water with the active sourdough starter and then mix in the flour, stirring until there are no more lumps.
• Cover the bowl with a clean, damp dish towel and let it rest for 30 minutes to 1 hour. This is what is known as an autolyse. You can read about this in the text above.
• After your dough has rested for 30 minutes to 1 hour, mix in the salt and rosemary and knead the dough for a couple of minutes. Because the dough is quite wet, this kneading is done with a spoon (I use a sturdy wooden spoon) and done by stirring, folding, and pulling. Work that dough by folding it, stirring it and stretching it with the spoon.
• Cover the bowl with the same dish towel and leave it to rest for about an hour.
• After one hour, you'll perform the first folding (check out my video above). Cover the bowl again and leave it for one more hour and then perform the second folding. If you've got time for it, you can perform one last folding after yet another hour. Cover the bowl in between. (If you've only got time for one folding then that is better than nothing).
• Once you have gone through the folding phase, leave the bowl on the kitchen counter, covered with that damp towel, for 3-5 hours or until you see good activity in the dough, which means the dough will have risen by at least 50 % but no more than 65%.
• After these 3+ hours, place the bowl in the refrigerator overnight. This will allow the flavors to develop slowly and give the baguettes a good crust and that deeply rich sourdough flavor.
• The next morning, take the bowl out of the fridge and place it back on the kitchen countertop. Leave it here for a few hours before proceeding to the baking phase. This will bring the dough to room temperature.

  I usually don't bake my breads until mid to late afternoon, but don't take my word for it. Your sourdough is different from mine and ambient temperature also plays a role, so you need to pay attention to your dough to know when it is ready to be baked. It will be at its peak once it is no longer rising but before it starts to deflate. This is the ideal time to put it in the oven. This timing is not an exact science but the change from one phase to the other also does not happen in a flash. Just pay attention to your dough and you'll be fine. A hint: As long as the dough is rising, the dough will be slightly curved downward at the edges of the bowl. Once it stops rising, the top will flatten out.

Shape and bake the baguettes.

• Clean your worktop and spread some flour onto it. Pour the dough onto the floured surface and gently fold one half over itself, then divide it into 4 equal pieces. Shape these pieces into rounds and leave them to rest for 20 minutes. Refer to the video for proper technique.
• Turn on your oven to 250º C / 480º F and place a baking tray in the oven. (The tray need to heat up for at least 20 minutes for best results).

  At the same time, place a glass dish on the floor of the oven. (You will pour boiling water into this tray at the same time as you put the breads in the oven. This will create steam which is important for the the breads to develop a proper crust).
• Cover your metal baguette tray (if using) with a piece of baking paper and set aside. Alternatively, flour a thick dish towel very well and create four folds in the towel to hold the shaped baguettes. (See the text above for more details).
• Then shape each round piece of dough like this:
• Gently stretch each ball into a small square. Fold about an inch (2.5 cm) of the top of the square down towards the center of the square. Pat down the seem; then grab the sides of the square (now rectangle) and pull them outward a little to elongate the dough a bit before folding in the sides, about an inch (2.5 cm) on either side, towards the middle. Then repeat. Which means folding the top down about an inch (2.5 cm), then stretching the dough out a bit to the sides before folding the sides in towards the middle.

  Now gently roll the dough until you get an even and elongated shape vaguely resembling a small baguette. Pinch the sides a bit to create the pointy ends. I have attached a video for visuals.
• Place the roll in its designated spot on the baguette tray, seem side down. Alternatively, place it in a fold in the prepared towel.

  Repeat with the remaining three pieces of dough.
• Put the kettle on and get some water boiling.
• Meanwhile, make three long incisions on the top of each baguette. Lengthwise and at a slight angle.
• When the water boils, pour a cup or two into the glass dish on the floor of the oven; then place the tray with the shaped baguettes on the hot baking tray in the middle of the oven.

  If you are not using a special baguette tray then remove the hot baking tray from the oven before covering it with a piece of baking paper; then gently transfer the baguettes from the dish towel to the tray.
• Bake for 15 to 20 minutes, turning the tray around after 10 minutes to ensure even baking.