Pour the fresh milk into a heavy-bottomed saucepan. Place the saucepan over medium heat.
Heat the milk gently, stirring frequently to prevent it from sticking to the bottom of the pan. Continue heating until the milk comes to a gentle boil.
Once the milk starts to boil, reduce the heat to low and continue to simmer. The goal is to evaporate most of the water content, so the milk will thicken and form a creamy consistency.
Add the salt and stir well. If using, you can also add the baking soda at this point to help with thickening.
For a creamier texture, stir in the sour cream or plain yogurt. This step is optional and can be skipped if you prefer a lighter consistency.
Keep simmering the milk mixture until it thickens further and starts to form clumps. This process may take about 30-45 minutes.
Once the mixture has thickened to a creamy consistency, remove it from the heat and let it cool. As it cools, it will continue to thicken.
Transfer the Urum to an airtight container and store it in the refrigerator. It can be kept for up to a week.
Enjoy your meal!