Step 3: To the pan, add 1 (16 ounce) can diced tomatoes, 1/2 teaspoon salt, dash of black pepper, and 1 teaspoon sugar. Simmer together until cooked through and blended, about 10 to 15 minutes.
Step 4: To a separate large saucepan, add 1/2 medium head cabbage, coarsely chopped. Pour the cooked tomato-onion sauce over the cabbage, stirring to combine. Simmer covered, stirring occasionally, until cabbage is wilted and blended with the tomatoes, about 20 minutes.