1 1/4 tbsp extra-virgin olive oil 3/4 tsp salt 3/4 tsp granulated sugar 3 large sweet onions, such as Vidalia (about 1 1/4 pounds), thinly sliced splash balsamic vinegar 1 1/2 lbs green beans, trimmed
1. In a large nonstick skillet, heat 1 tablespoon oil over medium-high heat. Add onions and season with 3/4 teaspoon kosher salt and 3/4 teaspoon granulated sugar. Cook, stirring often, until softened and just beginning to brown, 10 minutes. Scrape up any brown bits that begin to form on the bottom of the skillet; a flat-sided wooden spatula is particularly well-suited to this task. Add a splash of water (about a tablespoon) from time to time to de-glaze the browned bits. Reduce heat, if needed.
2. Cook, stirring occasionally, until onions are a deep golden brown color and very soft, about 30 minutes. Remove from heat and season with additional salt and a splash of balsamic vinegar. (Refrigerate in an airtight container, up to 1 day. Bring to room temperature before using.)
3. Meanwhile, in a large pot of boiling salted water, cook green beans until crisp-tender and bright green, about 6 minutes.
4. Drain and toss with 1 teaspoon oil. Season with salt and pepper.
5. Transfer beans to a platter and top with onions. Serve and enjoy!