In a large mixing bowl, combine the warm water and instant dry yeast. If using active dry yeast, let it sit for 5-10 minutes until foamy. (If using instant yeast, you can skip this wait time and add it directly with the flour).

Add the bread flour and fine sea salt to the yeast mixture. Mix with a wooden spoon or a stand mixer with a dough hook on low speed until a shaggy dough forms and all ingredients are combined.

Turn the dough out onto a lightly floured surface. Knead by hand for 10-15 minutes, or use a stand mixer on medium-low speed for 8-10 minutes, until the dough is smooth, elastic, and passes the windowpane test (you can stretch a small piece thin enough to see light through it without tearing).

Lightly grease the mixing bowl. Place the dough in the bowl, turning once to coat. Cover with plastic wrap or a damp kitchen towel. Let rise in a warm place for 1.5 to 2 hours, or until doubled in size.

Gently turn the risen dough out onto a lightly floured surface. Divide the dough into two equal pieces using a bench scraper. Gently pre-shape each piece into a loose rectangle or oval. Cover with a clean towel and let rest for 20 minutes. This allows the gluten to relax, making final shaping easier.

Lightly flour your work surface. Take one piece of dough and flatten it into a rectangle. Fold the top third of the dough down towards the center, pressing firmly to seal. Fold the bottom third up to meet the top edge, pressing firmly to seal. Fold the dough in half lengthwise, sealing the seam tightly with the heel of your hand. Gently roll the dough back and forth, from the center outwards, to lengthen it to about 12-14 inches (30-35 cm), tapering the ends slightly. Aim for an even thickness. Repeat with the second piece of dough.

Carefully transfer the shaped baguettes to a lightly floured couche (linen proofing cloth), a floured kitchen towel, or a baguette pan. Create pleats between the loaves to support their shape. Cover loosely with plastic wrap or a clean towel. Let rise in a warm place for 45-60 minutes, or until the dough is noticeably puffy and springs back slowly when gently poked. Meanwhile, preheat your oven.

About 30 minutes before baking, preheat your oven to 475°F (245°C) with a baking stone or inverted heavy baking sheet inside. Place an empty oven-safe pan (like a cast iron skillet) on the bottom rack of the oven to create steam.

Carefully transfer the baguettes onto a piece of parchment paper on a peel or directly onto your preheated baking stone/sheet. Using a sharp razor blade or lame, make 3-5 diagonal cuts (slashes) along the top of each baguette, about 1/4 to 1/2 inch deep. Angle the blade slightly for a better "ear".

Immediately place the baguettes in the hot oven. Pour about 1 cup of hot water into the empty pan on the bottom rack (be careful of the steam!). Quickly close the oven door. This creates steam for a crisp crust.

Bake for 15 minutes, then carefully open the oven door and remove the steam pan. Reduce the oven temperature to 450°F (230°C). Continue baking for another 10-15 minutes, or until the baguettes are deep golden brown and sound hollow when tapped on the bottom. You can spray the loaves with water a couple of times during the first 10 minutes of baking to enhance crust development, if desired.

Transfer the baked baguettes to a wire rack to cool completely before slicing and serving. Cooling is crucial for the internal structure and crust to set.