1. Place the cocoa and ¾ cup of the half-and-half into a small mixing bowl and mix with a fork until well blended. Add more half-and-half if needed to form a smooth paste.

2. Pour the coffee, sugar, and the remaining half-and-half into a medium heavy-bottomed saucepan.

3. Add the chocolate paste to the coffee mixture, mix well, and bring to a simmer.

4. Remove from the heat and add the vanilla.

5. Divide the mocha coffee among two mugs and top each with whipped cream.

6. Dust with chocolate shavings and cinnamon; serve immediately.