Baked Harvard Beets

3 cups cooked beets, diced
1/4 cup sugar
1 Tbsp. cornstarch
1/2 tsp. salt
1/3 cup vinegar
1 Tbsp. lemon juice
3 Tbsp. beet juice
2 1/2 Tbsp. butter

Place beets in casserole. Combine cornstarch, sugar and salt. Add vinegar, lemon juice and beet juice. Mix thoroughly. Pour over beets and dot with butter. Cover and bake at 350 degrees for 1 hour.