Method:

1. Place potatoes and onions in a large bowl.

2. In a screw-top jar, add vinegar, oil, garlic, red pepper, salt, sugar, and black pepper.

3. Cover with the lid and shake vigorously. Toss potatoes with dressing.

4. Refrigerate, covered, overnight.

5. For best flavor, allow to come to room temperature before serving.

6. Taste and adjust seasonings if necessary.