Pour the milk into a heavy-based saucepan and place over medium heat. Warm gently, stirring occasionally to prevent it catching on the bottom. Heat to 85 - 90 degrees Celsius or until steaming with small bubbles forming around the edges, but do not let it boil.
Remove the saucepan from the heat and stir in 2 tablespoons of vinegar. Gently stir once or twice and allow the milk to sit (don't stir too vigorously). Within a minute it should separate into white curds and pale yellow whey. If it has not fully separated, add a little more vinegar and leave for another minute.
Cover and let it rest undisturbed for 10–15 minutes so the curds fully set.
Line a sieve with a clean tea towel or cheesecloth and place it over a bowl. Carefully pour the curds and whey into the sieve and allow to drain for 5–10 minutes for soft cottage cheese, or longer for firmer curds.
For a classic cottage cheese texture, gently rinse the curds under cold water while lightly breaking them apart. Drain again briefly.
Transfer to a bowl and stir through salt and cream, if using. Adjust seasoning to taste. The finished cottage cheese should be soft, lightly creamy and slightly tangy.