Preheat oven to 400 degrees F. Place rack in middle of oven.
Wash and scrub the whole beets to clean off any dirt. Leave the beet whole unless you have some extra large ones (if extra large, cut in half). Trim off the stems (leafy tops) and ends of the beets. Reserve the beet leaves for a recipe using them.
Beet Greens - How To Cook Fresh Beet Greens
Washed and Trimmed Beets
On a large baking sheet, cover with aluminum foil. Place prepared beets, in a single layer, on top. Toss lightly with some olive oil to coat the beets. Place another large sheet of aluminum foil on top of the beets and crunch up the sides of the aluminum foil together to seal.
Beets ready to roast in the oven.
Place in oven and roast approximately 1 to 2 hours (depending on the size of your beets) or until tender and easily pierced with the tip of a paring knife. Remove from oven and take off the top foil. Set aside to cool enough to handle.
When cool enough to handle, peel the skin off. They should peel easily by hand, but you can use a paring knife if you want.
Peeling the cooled beets
Once the beets are cool enough to handle, either store in the refrigerator whole or cut each beet into 1/2-inch cubes and place in a large bowl.
Make the dressing by whisking together the vinegar, mustard, salt, and pepper. Add the olive oil in a steady stream, whisking constantly to form an emulsion. Pour the dressing over the beets and toss to coat.
Add 2 tablespoons of horseradish and toss again. Taste and add additional salt, pepper, and/or horseradish if desired.
Transfer to a serving platter and scatter the chopped chives over the top. Serve at room temperature.
Yields approximately 4 cups or 6 to 8 serving.