Simpliest hard crust bread

I wonder how I can bake French bread with a hard crust, I tried different methods, at the end I found the answer, it is so simple - very very hot oven. 

However, it is impossible to have 300°c-400°c environment in domestic oven... so... you can either buy a stone board or an iron-cast Dutch oven!

This recipe requires a 6-8quarts iron-cast Dutch oven. I only have one which is close to 6 quarts, it works too.

Ingredients
6 cups bread flour - I used multi-cereal flour
2 1/2 tsp salt
1/2 tsp instant or active-dry yeast*
2 2/3 cups water at room temperature

*1/4 tsp yeast needs 16hours rise, 1/2 tsp yeast needs 12hours rise

Instructions
Previous evening prepare your dough

1. In a large mixing bowl, mix flour & salt, mix well.

a/ If you use active-dry yeast-
mix it with 1/3 cup warm water (maximum 37°c), set aside for 10mins to activate the yeast

Then pour the yeast mixture to flour mixture, mix with water until it is well combined

b/ If you use instant yeast
Add it in flour & salt mixture and add in water, mix well until combined

2. After forming a dough, it is wet and sticky, cover plastic wrap and leave it rise during the night
When it rises double the size, it is ready

The next day
1. Prepare for the 2nd rise: place a towel, sprinkle some flour. Then place 2 baking sheets (long enough to cover the whole dough) forming a cross, sprinkle some flour

2. Flour the working surface, fold the dough - from right to left, left to right, top to bottom, top to bottom

3. Place the dough on the baking sheet with the seam faces the bottom, cover the dough with baking sheets and then the towel
If the towel can't wrap completely the dough, place one more towel on the top

Leave it rise for 1-2hours or until the size is doubled

4. 30mins before you put the dough to the oven to bake, place a cast-iron Dutch oven with lid into the oven, then turn on the oven to preheat at 250°c

5. After 30mins, take out the Dutch oven, open the lid, slide the dough in it
If the dough stick on the baking sheet, then flip the dough in the Dutch oven, remove the baking sheet

Do not worry if the shape doesn't look good. It will be nicely formed in the oven

6. Cover the Dutch oven with the lid, put it back to the oven
Turn down the temperature to 230°c and bake for 40mins

7. After 40mins, remove the lid and bake for another 10mins
The crust should be harden during this time

8. Remove the bread and cool it on a wire rack before serving

Enjoy!