This relish goes well with grilled or roasted chicken, pork, turkey, or duck.
In a small saucepan, heat oil over medium. Add shallots and ginger, season with salt and pepper, and cook until softened, 3 minutes. Add plums, sugar, and 1/2 cup water. Bring to a simmer and cook until plums have softened (add 1/4 cup water if needed), about 12 minutes. Stir in vinegar and zest. Season with salt and pepper.