Place a rack in the center of the oven and preheat to 400 degrees F. Cut off the beet leaves near the tip of the beet (save the beet greens for another use) and scrub the beets well. Toss beets with 2 tablespoons olive oil, then wrap in tin foil (small beets can be wrapped together; large beets should be wrapped separately). Place beets on a baking sheet to catch any juices, then roast for 50-60 minutes, until fork tender (time will vary depending upon the size of the beets.) Check the beets every 20 minutes to ensure they are not burning on the bottom. If they begin to scorch, drizzle with a little water, then rewrap and continue cooking. Remove from oven and set aside until cool enough to handle. Slip off beat skins and slice into 1/2-inch thick wedges. (At this point, the beets can be refrigerated in an airtight container for up to 1 week.)
Place 1/3 of the roasted beets into a blender or food processor with the stock. Puree until smooth (the mixture will be very liquidy), then transfer to a saucepan and bring to a gentle simmer. Reserve remaining beet wedges.
In a large, sturdy pot or Dutch oven, heat the remaining 2 tablespoons of olive oil on medium-low. Add shallot, parsley, garlic, and cook until tender, about 5 minutes.
Add the rice to the pot and stir to coat, then add wine and cook for 2 minutes.
Carefully add 2 full ladles of the beet puree, salt, and pepper. Stir and simmer over low heat until most of the liquid is absorbed, 5-10 minutes. Continue to add the beet puree, 2 ladles at a time, stirring every few minutes and ensuring the rice isn’t sticking to the bottom. With each addition, continue to cook and stir until the mixture seems almost dry, then add the next 2 ladles. Continue until you have used all of the liquid and the rice is soft and creamy; about 25 minutes. Stir in reserved beet wedges. Serve immediately, topped with Parmesan cheese.
TO MAKE AHEAD: Roast and store the cooked, peeled, and chopped beets in the refrigerator for up to 1 week. Then pick the recipe up at Step 2 when you're ready to prepare the risotto.
TO STORE: Cooked risotto will keep in an airtight container in the refrigerator for up to 3 days.
TO FREEZE: You can freeze risotto in an airtight container for up to 2 months. Defrost overnight in the fridge before warming. Note that the texture will change slightly once thawed and reheated, however. If you don't mind this, go ahead and freeze. Otherwise, I suggest eating leftovers within 3 days.
TO REHEAT: Rewarm gently on the stovetop or in the microwave, adding vegetable or chicken stock (or in a pinch, water) as needed to prevent the risotto from drying out.