El Bar Americano en España by Pedro Chicote (1927, p.110)

1 tablespoonazúcar en polvo — Inherited from the Spanish grog formula.base
agua hirviendo — Used as the remainder of the drink.dilution
1 slicerodaja de limón con clavos — rodaja de limón incrustada de 3 ó 4 clavosgarnish
1 copitamenta — Substitutes for cognac or rum in the Spanish grog.modifier
  1. Prepare the same way as the Spanish grog, replacing the cognac or rum with a copita of mint liqueur.
  2. Serve hot in the same glass.

Chicote defines this as the same combination as the Spanish grog with mint in place of cognac or rum.