Homemade Red Onion Jam
In a large saucepan with a lid, heat oil over medium. Add onions, season with salt and pepper, and toss to coat. Cover and cook, stirring occasionally, until onions are very soft, 20 to 25 minutes.Advertisement
Add vinegar and sugar; simmer over medium-low heat, uncovered, stirring occasionally, until syrupy and jam-like, about 30 minutes. Let cool.