To make the oleo saccharum, crack the cinnamon sticks with a mortar and pestle, and add them to a nonreactive container along with the powdered sugar, vanilla beans and Meyer lemon peels (reserving the lemons). Muddle the peels, then let the mixture set for a day. In a separate nonreactive container, add the whole milk and crushed graham crackers, steep in the refrigerator for 1 day, and strain out the solids.
Juice the Meyer and regular lemons, and add them to the oleo saccharum along with the first four ingredients, and stir to combine.
To clarify the punch, slowly pour the lemon-liquor mixture into the strained whole milk.
Once it has started to curdle, place it in the refrigerator for 1 or 2 days, then strain it through a cheesecloth-lined chinois and then a coffee filter if necessary. Keep the punch chilled.
To serve, pour 3 oz in a mug over ice.
Garnish with ground nutmeg.