1. Place beets in an 8-inch square baking pan. Add 1/2 inch water. Cover pan tightly with foil and bake in a 375° regular or convection oven until beets are just tender when pierced, 45 to 60 minutes. When cool enough to handle, peel and cut into matchstick-size strips (see notes).
2. In a bowl, combine beets and 1/3 cup sour cream and mix gently to coat; if you'd like your salad more moist, stir in a little more sour cream. Stir in dill and salt, pepper, and vinegar to taste.