Leipäjuusto is a traditional Finnish cheese, made from cow's milk, that is set and then cooked under the grill. It is sometimes referred to as squeaky cheese because of the sound it makes when you eat it. This cheese is often served as part of a Finnish breakfast with cloudberry or cranberry jam.
Do not use UHT milk. Fresh pasteurised milk is fine.
You can find calcium chloride and rennet online and in some specialty food shops. These ingredients will help produce a firmer cheese.