Note from Ricardo
Beet juice is available in grocery stores, but since you only need a very small amount for the icing, here are a few ways to get the quantity you need for this recipe. Grate 1 peeled beet (raw or cooked). Over a bowl, using your hands, squeeze the grated beet to extract as much juice as possible. Alternatively, you can save the juice that accumulates in the bottom of a bag of vacuumed-sealed or canned store-bought cooked beets.