Cover, and 5 minutes later adjust heat so mixture simmers steadily.

Adjust heat so mixture simmers steadily but not violently.

Bring to a boil, then adjust heat so that mixture simmers steadily but not vigorously.

Return ribs to pot; adjust heat so mixture simmers steadily but not violently, and cover.

Cover, turn heat to high, bring to a boil and adjust heat so mixture simmers steadily.

Lower the heat so the mixture simmers steadily.

Add escarole, along with 1/2 cup water, and adjust heat so mixture simmers steadily.

Bring to a boil, then cover, and adjust heat so mixture simmers steadily.

Partially cover and adjust heat so mixture simmers steadily.

Bring the water to a boil, then lower the heat so that the water simmers steadily and creates steam.