In a large bowl, combine warm water, sugar, and active dry yeast. Stir and let sit for 5-10 minutes until foamy.
Add 2 c. (240g) all-purpose flour, salt, and olive oil to the yeast mixture. Stir until combined. Gradually add the remaining 2 c. flour (240g), a half a cup at a time, until a shaggy dough forms.
Turn dough onto a lightly floured surface and knead for 5-7 minutes until smooth and elastic.
Shape dough into a ball, place in an oiled bowl, cover with a damp towel, and let rise in a warm place for 1 hour until doubled.
Punch down dough. Choose your loaf size:
For one large loaf: Roll dough into a 16x10-inch rectangle. Roll tightly from the long side, pinch the seam, and tuck ends under.
For two smaller loaves: Divide dough into two equal portions. Roll each into a 10x8-inch rectangle. Roll tightly from the long side, pinch the seam, and tuck ends under.
Place loaf (or loaves) on a parchment-lined baking sheet, spaced apart if making two. Cover loosely and let rise for 30 minutes. Preheat oven to 400°F (200°C).
In a small bowl, whisk 1 large egg with 1 tbsp. water (or milk) until smooth. Gently brush the egg wash over the risen loaf (or loaves). Using a sharp knife, make diagonal slashes about ½ cm deep.
Bake on the middle rack:
One loaf: 20-25 minutes, until golden and hollow-sounding when tapped.
Two loaves: 18-20 minutes, until golden and hollow-sounding when tapped.
Cool on a wire rack for 10 minutes before slicing into ~18 slices (one loaf) or ~9 slices per loaf (two loaves).
Notes
Egg wash after the second rise creates a smooth, glossy crust. Use milk for a richer color.
Slashing just before baking ensures even expansion and preserves loaf shape.
Check smaller loaves at 18 minutes to avoid overbaking and keep the crust soft.
Water for dough should be 90-110°F to activate yeast.
Store in a plastic bag to maintain softness for 1-2 days or freeze slices for up to 1 month.