Put a pan on medium heat. Chop finely the onions and sauté in a pan with a little olive oil. Let them simmer for 3-4 minutes. Add the rosemary to get its aromas. Chop the garlic, add it to the pan and mix. Remove the peels from the ginger. Rub the ginger into the pan and mix well. Then, add the sugar and mix well so as to melt until the sauce thickens. At this point we can also add balsamic and worcestershire sauce. Stir again for 1-2 minutes, as the secret is in good stirring! Finally, remove the rosemary and add the 4 tablespoons of soy sauce and a little ketchup, paprika and 1/2 teaspoon, for a more intense taste, and stir until the sauce thickens. Transfer mixture to mulberry until smooth.