To a small saucepan, add turmeric, ginger, lemon juice and leftover lemon rind, maple syrup (optional), cayenne (optional), and filtered water. I personally didn't think it needed any sweetener, but sweeten to taste.
Bring to a simmer (not a boil) over medium to medium-high heat (~3 minutes). Then turn off heat.
Set a small strainer over serving glasses and divide between two mugs. Enjoy. If the tonic is too potent for you, dilute with more hot/warm water.
Store (strained) leftovers in the refrigerator up to 2-3 days. Reheat on the stovetop until just warm.
*Nutrition information is a rough estimate calculated without cayenne or sweetener. *Clear mugs from Crate and Barrel. Small strainer from Amazon.