Preheat your oven to its lowest temperature, around 86°F (30°C), with a dish of boiling water inside for steam.

In a stand mixer fitted with a dough hook, combine water, bread flour, bread improver, instant dry yeast, sugar, and vitamin C powder. Mix on low speed, then increase to medium and knead for about 8 minutes until smooth and elastic.

Turn the dough out onto a lightly floured surface, flatten it, and cut into six equal pieces. Shape each piece into a log.

Place shaped logs in the warm oven for proofing covered loosely with a kitchen towel for 1.5 to 2 hours until they quadruple in size.

After rising, remove from oven and preheat to 400°F (200°C). Prepare a baking method for steaming using an iron skillet filled with hot water.

Score each dough log at a 45-degree angle with 2-3 diagonal slashes.

Quickly pour hot water into the skillet, place baguettes on a baking sheet, and bake for 7-8 minutes with steam, then remove the skillet and bake for another 4-5 minutes until golden brown.

Remove from the oven, cool on a wire rack for a few minutes, and brush with melted vegan butter before cooling fully.