Wash the beets thoroughly, then peel and dice them into small cubes.

Place the diced beets in a saucepan and cover with water. Bring to a boil, then reduce heat and simmer for about 30-40 minutes until tender.

In a separate saucepan, combine vinegar, water, sugar, salt, peppercorns, mustard seeds, and garlic. Bring to a boil, stirring until the sugar dissolves.

Once the beets are cooked, drain them and add them to the pickling liquid. Let it cool slightly, then transfer to a jar and refrigerate for at least 24 hours before serving.