Preheat your oven to the lowest setting, around 86°F (30°C). Place a small bowl of boiling water inside.

In a stand mixer, combine water, bread flour, bread improver, yeast, sugar, and vitamin C powder. Mix until combined, then increase speed for 8 minutes.

Remove dough from bowl, place on floured surface, divide into six pieces, shape into logs.

Place shaped dough logs back in the warm oven to proof for 1.5 to 2 hours.

Remove dough, preheat the oven to 400°F (200°C). Set up steam-generating method with water.

Score each baguette at a 45-degree angle with a razor blade or bread lame.

Bake baguettes, pouring hot water into the skillet for steam. Bake for 7-8 minutes, then an additional 4-5 minutes without steam.

Remove from oven, let cool slightly on a wire rack, and brush with melted vegan butter.