Grease a large shallow pan with butter.

Combine condensed milk, 1 tablespoon butter, cocoa powder, cinnamon, and cayenne pepper in a large saucepan.

Bring to a boil over medium heat, stirring constantly.

Reduce heat to medium-low and cook, stirring constantly, until the mixture pulls away from the sides of the pan and has the consistency of thick frosting (15-20 minutes).

Pour the mixture into the greased pan and let cool completely (about 1 hour).

Line a baking sheet with wax paper.

Grease your hands with butter and shape the cooled truffle mixture into 1- to 2-inch balls.

Place the truffle balls on the wax paper.

Melt chocolate in a double boiler or heatproof bowl over simmering water.

Stir until melted and smooth.

Optionally, temper the chocolate for a shiny finish.

Decorate each truffle with nonpareils, lump sugar, disco dust, red candies, and quins.

Refrigerate for at least 1 hour before serving.

Transfer to mini cupcake liners or paper candy cups and serve.