In a large bowl, stir together the sourdough starter with water, milk, yeast, sugar, ricotta cheese and salt. Add the flour and mix with a wooden spoon until the dough comes together.
Transfer the dough onto a lightly floured surface and knead until smooth and elastic, about 8 min. If the dough seems too sticky, dust with just a little bit more flour.
Drop a little oil in the bowl and swirl around to coat the bottom. Shape the dough into a ball and place in the oiled bowl. Cover with a damp kitchen towel and let rise until doubled in size, about 4 hours.
Scrape the dough onto a floured surface and fold for 3-4 times. Shape it into a loaf and place on a parchment paper. Cover with the towel and let rise for 40-60 min. Meanwhile, place a lidded baking dish into the oven and preheat to 250 C.
Transfer the dough to the baking dish. Reduce the oven temperature to 230 C. Cut some scores over the bread and bake for about 30-35 min. with the lid on.
The bread is done when sounds hollow if you tap at the bottom. Remove from the oven and let cool completely on a rack.
Cooled bread would be nicely sliced. Enjoy!
