Remove the leaves from the beets, but leave the roots and an inch of stem.

Look at the size of your beets. Use a measuring tape to measure them, or you can eyeball it and do a little math. If they are 5 inches in circumference, cook 15 minutes and add three minutes for each half an inch, so nine inch beets would go for 36 minutes. If you don't have a tape measure, you can get the circumference by multiplying the width by π. Let the beets natural release for 10 minutes, then quick release,

Put the beets in water to cover and bring to a boil. Boil for 25 minute or until the beets are tender.

Put the beets in foil and roast them at 350 for about an hour or until they yield to the touch.

Let the beets cool until cool enough to handle. Use your hands to slip off the peel, and cut of the stem and roots. Slice the beets, then put them in a non-reactive bowl, and cover them with the left over watermelon pickle juice. Refrigerate until nicely chilled.

If you want, you can put them in canning jars and use the hot water method to can them,