To cook the beets, simply wash them, place in a large pot, cover with water, about 1-2 inches over and boil for 40-50 minutes. To preserve the color, add about 1 tablespoon of vinegar, and season with 1 teaspoon of salt. Cook until tender, drain, cool, and peel. OR use a pressure cooker, which is what I use, that instruction is listed in the Recipe Notes section below.
Slice the beets, about ½ to ⅜ inch thick slices.
Mix the corn starch, sugar, salt, and pepper in a pot or large sauce pan, slowly whisk in the water then mix in the vinegar.
Heat on medium heat, stirring or whisking constantly until the mixture thickens and comes to a boil. Keep stirring and boil for 1 minute.
Reduce heat to a simmer and add the beets. Simmer until the beets are heated through and hot.