Pane mafalda palermitana

This bread is soooo good.  It goes great with all kinds of Antipasti and a good dip is wonderful too.
recipe:
250 g wheat flour T405
250 g semola di grano duro
30 g sourdough starter
100 g wheat flour T405
100 ml water
15 g yeast
300 ml tepid water
1 tsp olive oil
2 tsp salt
1 egg yolk
1 tsp sesame seeds
olive oil to brush

Plan the day before, put 25 g of sourdough starter with 100 g flour and 100 ml tepid water in a bowl and stir. Set it on a table at room temperature without a lid.  It will take 12 hours and it bubbles a bit.

 
In a kitchen machine add 60 g of your bubbly mass, add 250 g flour and 250 g of semola duro, the yeast and the salt. Get the water in and knead for 3 to 4 minutes.
Put in a bowl and let it rest for 30 minutes.
After that time, put it on a floured surface and fold it a couple of times. It will be a very soft dough.

Back into the bowl and close it with a plastic bag or a lid and put it in a place not warmer then 18 C.
I put my bowl in the  basement with 13 C for 15 hours.
The back into the kitchen and without a lid for 1 more hour.

Fold it gently and do not overwork it. Set it on some baking paper with a bit of semolina and let it rest 30 more minutes.
Brush it with egg yolk and sprinkle it with sesame seeds.

220 C with steam for 10 min, 200 C without steam for 30 min,  after half the time brush it with some olive oil.