Sun-dried tomatoes add subtle sweetness that balances out the bite of broccoli rabe.
Discard tough ends of broccoli rabe, and cut remainder into 1 1/2-inch lengths. Rinse, shake off excess water, but do not dry.
In a 5-quart saucepan with a tight-fitting lid, heat 1 tablespoon oil over medium heat; swirl to coat bottom of pan. Add garlic; cook, stirring, until golden, about 1 minute.
Add rinsed broccoli rabe (with water still clinging to leaves). Sprinkle with sugar; cover and cook until wilted, 5 to 6 minutes. Toss with sun-dried tomatoes, vinegar, and remaining 2 teaspoons oil. Season with salt and pepper.