Prepare 2 cups of strong coffee or espresso and keep it warm while preparing the spiced milk mixture and add the milk, brown sugar, cocoa powder, cinnamon, nutmeg, vanilla extract, and cayenne pepper if using to a small saucepan. Heat over medium-low heat, whisking frequently until the sugar dissolves and the mixture becomes smooth.
Continue warming the milk mixture for 2–3 minutes, allowing the cinnamon and chocolate flavors to infuse without bringing it to a boil.
Slowly pour the brewed coffee into the spiced milk mixture and whisk gently until everything is fully combined.
Taste the coffee and add more brown sugar if you prefer a sweeter drink or extra cinnamon for a stronger spice flavor.
Divide the Mexican coffee between two mugs and top with whipped cream if desired.
Sprinkle a little cinnamon or cocoa powder over the whipped cream and serve immediately while hot.
