To begin, pour the milk into a wide, heavy bottomed pot. Heat gently over low to medium heat until it just begins to steam and small bubbles form at the edges. Do not let it boil. Move to cream addition.
Stir in the double cream slowly, ensuring it blends evenly with the milk. Keep the heat steady so the mixture develops a thick surface layer. Transition to simmering.
Maintain a very low simmer for 1 to 1.5 hours. As the surface forms a thick layer of cream, avoid stirring. This crust is the foundation of Kajmak. Move to collecting the crust.
Using a wide spoon, carefully lift the cream crust from the surface and place it in a shallow dish. Sprinkle lightly with salt. Allow the pot to continue simmering so more crust can form. Continue repeating.
Repeat the process of collecting crusts every 20–30 minutes. Each layer should be salted lightly before being placed into the dish. Once enough layers are collected, move to resting.
Cover the dish loosely and allow it to rest at room temperature for several hours. This allows flavours to meld and the texture to thicken. Transition to chilling.
Transfer the Kajmak to a sealed container and refrigerate overnight. The flavours will deepen, and the texture will become spreadable. Proceed to serving.
Serve Kajmak slightly softened, spread over warm bread or alongside grilled meats such as ćevapi. Presentation tip: drizzle with a few drops of olive oil before serving for added richness.