Wipe up the excess beet juice with a soft, nonabrasive sponge. Anything that's abrasive could scratch the countertop.
Dampen the sponge and add some liquid dish soap to it. Gently scrub at the beet stain until it starts to lessen.
Shake some baking soda on the stain and continue scrubbing it with the dish soap and damp sponge.
Remove any remaining beet juice residue with vinegar. Pour straight, undiluted vinegar directly on to the stains. Allow the vinegar to sit for a few minutes, then scrub it away with a sponge. Add a little more baking soda to add light abrasion if necessary.
Rinse the countertop with clean water and wipe it dry with a paper towel.