Combine the milk, chilies, and cinnamon sticks in a heavy large saucepan
. Bring to a simmer over high heat. Remove from the heat. Cover and steep
for 15 minutes. Whisk
in the espresso, sugar, and 1 cup of cocoa powder
. Bring the hot chocolate to a simmer
, whisking often. Discard the chilies and cinnamon sticks
Meanwhile, whisk the powdered sugar and remaining 1/4 cup cocoa powder in a large bowl to blend
. Add the cream and whisk until the mixture is thick.
Ladle the hot chocolate into 8 mugs. Spoon the chocolate whipped cream
atop and serve immediately.