Bring the milk to the boil in a large saucepan over moderate heat. Remove from the heat and stir in the lemon juice. Let stand until the curds and whey separate. Line a sieve with a double layer of muslin. Place the sieve in the sink and pour in the curdled milk, draining off the whey. Place the sieve over a bowl and stand for 20 minutes.
Tie the muslin up and gently squeeze to remove any remaining liquid. Flatten the mixture into a round, place a weight on top (such as a heavy can inside a saucepan) and stand at room temperature for 2 hours or until the cheese is firm enough to cut.