Step 1 Combine the sugar and water in a large heavy skillet and bring to a boil over medium-high heat, mixing constantly, until the sugar dissolves, 3 to 4 minutes. Reduce the heat and simmer until the sugar begins to turn golden, 20 minutes.
Step 2 Add the tomatoes, warm orange juice and zest, bring to a boil, reduce the heat and simmer until the tomatoes are soft and the liquid has reduced to a thick syrup, about 30 minutes. Cool.