Roast the butternut squash. Peel it and remove the seeds. Chop it in 1 inch cubes. Transfer on a baking sheet lined with parchemt paper. Roast in the oven preheated to 425F for 25-35 minutes. Let it cool down 10 min.
Using an immersion blender or food processor transform the roasted butternut squash into a thick puree.
In a bowl add the flour, instant yeast, turmeric and sugar. Mix with a fork.
Add the butternut squash puree and salt. Mix.
Slowly pour in the luke warm water, a bit at the time. Mix
Add 2 Tbsp olive oil. Mix.
Using your clean hands start combining the ingredients togehter in order to obtain a sticky dough. It should take 5 minutes. Wash your hands and take a larger bowl. Grease the bowl with 2 Tbsp olive oil. Set apart.
Dust a flat surface with some flour, transfer the dough and knead it a bit more to form a smooth ball. If the dough is too sticky, add some more flour, a bit at the time. Transfer the dough in the large bowl you just greased with oil.
Cover with plastic wrap and a kitchen towel and let it rest 2-3 hours in a warm place. The switched-off oven will work. The dough will be ready when it will double the size.
Transfer the dough on a baking sheet greased with 3 Tbsp olive oil and spread it out with your clean hands to cover the whole surface. Let it rest for 40 minutes on the countertop uncovered.
Poke the focaccia with your fingers to leave that lovely dimples on the surface. Sprinkle the minced rosemary on top and 2 tsp sea salt too. Drizzle 2 Tbsp olive oil on top.
Bake in preheated oven to 400F for 30min. Let it cool down 10 minutes, cut in cubes and enjoy!