Mix the instant yeast and sugar in a small mixing bowl. Add the warm water and stir to dissolve. Add one tablespoon of the flour and mix.
For best results, let the yeast mixture sit for 5–10 minutes until it becomes frothy.
In another large bowl, combine the flour and salt.
Make a well in the center and pour in the yeast mixture and the remaining warm water. Mix with a wooden spoon or your hand until a rough dough forms.
Transfer the dough to a lightly floured surface.
Knead for about 10 minutes until the dough becomes smooth, elastic, and slightly sticky. If the dough is too sticky, add a little more flour.
Shape the dough into a ball and place it in a lightly oiled bowl. Cover the bowl with a damp cloth or a piece of plastic wrap. Let the dough rest and rise in a warm place for 1-2 hours, or until doubled in size.
After the first rise, gently deflate the dough and turn it out onto a floured surface.
Divide the dough into two equal pieces.
Working with one piece at a time, shape the dough into a rectangle. Fold the long edges into the center, then roll the dough into a log, pinching the seams closed. Roll it back and forth to elongate the dough to about 12-14 inches (30-35 cm) long.
Place the shaped dough on a baking tray or baguette pan. Cover the dough loosely with a cloth and let it rise for 45 minutes to 1 hour.
Preheat your oven to 480°F (250°C) and put a shallow pan on the bottom oven rack.
Just before baking, pour 1 cup of boiling hot water into the shallow pan at the bottom of the oven. This is called a water bath and it will create steam, which helps form a crispy and crusty baguette.
Using a sharp knife or a razor blade, make 3-4 diagonal slashes on the top of each baguette. This helps control the expansion of the bread as it bakes.
Place the baguettes directly on the baking sheet. Bake for 10 minutes and then remove the water bath pan. Keep baking the baguettes for 10-15 minutes until the crust is golden brown and the baguettes sound hollow when tapped on the bottom.
Transfer the baked baguettes to a wire rack to cool completely before slicing.