Preparation In a 2-quart microwave-safe casserole with a lid microwave the beets with the water, covered, at high power (100%), stirring every 2 minutes, for 6 to 15 minutes, or until they are tender when pierced with a fork, transferring them as they are cooked to a cutting board, and let them cool. Reserve 1/4 cup of the cooking liquid in the casserole. Peel the beets and slice them. In a small bowl dissolve the cornstarch in the vinegar and stir the mixture into the reserved cooking liquid with the sugar and salt to taste. Microwave the mixture at high power, stirring after 1 minute, for 2 minutes, or until the mixture is thickened, stir in the beets and the butter, and microwave the mixture at high power for 1 minute, or until the beets are heated through.
Preparation In a 2-quart microwave-safe casserole with a lid microwave the beets with the water, covered, at high power (100%), stirring every 2 minutes, for 6 to 15 minutes, or until they are tender when pierced with a fork, transferring them as they are cooked to a cutting board, and let them cool. Reserve 1/4 cup of the cooking liquid in the casserole. Peel the beets and slice them. In a small bowl dissolve the cornstarch in the vinegar and stir the mixture into the reserved cooking liquid with the sugar and salt to taste. Microwave the mixture at high power, stirring after 1 minute, for 2 minutes, or until the mixture is thickened, stir in the beets and the butter, and microwave the mixture at high power for 1 minute, or until the beets are heated through.