In a large mixing bowl, sift together the flour, salt and oregano.
In a separate bowl, combine the warm water, milk, sugar and yeast. Let the mixture sit for about 5 minutes to bloom the yeast.
Combine ricotta and melted butter into the yeast mixture.
Combine the wet and dry ingredients and mix, scraping down the sides of the bowl with a rubber spatula, until a shaggy dough forms.
Turn out the dough on a clean flat surface and knead for 8-10 minutes until the dough is smooth and elastic. The dough should be slightly stretchy (this means the gluten has relaxed).
Place the dough into an oiled bowl and cover with plastic wrap. Leave the dough to rest for about 30 minutes until doubled in size.
Preheat the oven to 425 F (218C).
Punch the dough down and divide into 12 dough balls. Roll out each ball into a rope about 10 inches long, and twist to form a loose knot shape.
Place the knots onto a baking tray lined with parchment paper.
Whisk together the egg yolk and water in a small bowl, and brush the mixture on to each of the rolls. Optional: sprinkle on some black pepper or garlic powder at this step if desired.
Bake for 15-17 minutes until golden brown and puffy. Optional: brush a little olive oil or garlic butter over the tops of the rolls. Serve warm.