Cook until tomatoes soften slightly, adding juice if sauce seems too thick, about 5 minutes.

Put the tomatoes cut side down in the skillets and cook over high heat about 2 minutes, covered, until the tomatoes soften slightly.

Then add a large handful of cherry tomatoes and leave to simmer for another 15 minutes until the tomatoes have softened.

Stir in the tomatoes and continue to cook about five minutes longer, just until the tomatoes have softened.

Cook about 10 minutes, until the tomatoes have softened and are thick.

When the tomatoes have softened significantly but still hold their shape, gently shuffle them to one side of the pan.

Bring to a simmer, and cook until tomatoes soften, 5 to 7 minutes.

Cook until tomatoes have softened, about 10 minutes, then proceed as above.

As tomatoes soften, break them with a whisk, and stir.

Stir in tomatoes and cook about 5 minutes, until tomatoes soften completely and lose their shape; do not brown.