Preheat oven to 425. Cut the beet in half. Wrap each half in aluminum foil. Put the foil packets on a baking sheet and roast until soft, about 1 hour (turn once during roasting). Remove from the oven and let the packets cool until cool enough to handle. Then open the packets and peel the beets (the peels should slip off easily). Let cool completely. (You can roast the beets up to a day before and refrigerate them overnight in the foil packets before peeling). Cut the beets into chunks.
Add tomato, cucumber, onion, bell pepper and garlic to the container of a strong blender. Blend for a few seconds until the components aren't distinguishable from each other. Add the beet, 1/2 t salt, 2 tablespoons of vinegar, the oil and the Tabasco. Blend until the mixture is smooth but still has some texture. Taste, and add more vinegar, oil or salt, depending on your taste.
Chill, covered, for at least 3 hours before serving. This gazpacho keeps in the refrigerator for about 5-6 days. It is wonderful on its own, but for a riff on borscht, it can be garnished with a dollop of sour cream or yogurt.