31.   Cook until mixture thickens, a couple of minutes.

32.   Cook, over medium heat, stirring constantly, until mixture thickens and boils.

33.   In another medium bowl, mix condensed milk, lemon juice, lemon rind or extract and egg yolks until mixture thickens.

34.   Mixture should thicken.

35.   Mixture will thicken and rise in bowl as air is incorporated.

36.   Place over hot water, then cook and stir until mixture thickens.

37.   Place over medium heat and cook, stirring constantly with a wooden spoon until the mixture thickens and steam starts rising.

38.   Reduce heat to medium and cook, stirring frequently, until mixture thickens.

39.   Return saucepan to medium-low heat, and stir with a wooden spoon until mixture has thickened enough to coat the back of the spoon.

40.   Return to heat, and cook slowly until mixture thickens.