Easy Pickled Red Onions

Divide sliced onions, garlic halves, ginger slices, and peppercorns among 3 pint-sized jars.

Combine water, apple cider vinegar, distilled vinegar, maple syrup, and salt in a saucepan. Bring to a simmer over medium heat, stirring occasionally. Remove from heat and ladle vinegar mixture into each jar. Gently press down on onions with a spoon until they are submerged. Allow to sit, uncovered, until liquid is room temperature, about 30 minutes, then cover and store in the refrigerator.