Layered Mexican Hot Chocolate Pudding

1. Step 1In medium saucepan, whisk together 2 cups milk and 1/4 cup sugar and bring to a simmer.
2. Step 2In medium bowl, whisk together cocoa powder, cornstarch, salt, and remaining 1/4 cup each sugar and milk. Gradually whisk in hot milk mixture, then return to saucepan and bring to a simmer, stirring occasionally.
3. Step 3While mixture is coming to a simmer, add egg yolks to same medium bowl (no need to clean) and whisk to combine. Whisking constantly to prevent curdling, spoon about ¼ cup of warm milk mixture into eggs to combine. Whisk egg mixture back into milk mixture.
4. Step 4Whisking constantly, simmer pudding until it is slightly thickened and whisk leaves a ribbon-like trail when lifted, 2 to 3 minutes.
5. Step 5Remove from heat and stir in vanilla. Scatter chocolate over pudding and let sit 1 to 2 minutes to melt, then stir until smooth. Transfer to large bowl and place piece of plastic wrap directly onto surface to prevent skin from forming. Let cool 30 minutes, then refrigerate until chilled, 1 hour. (This is a good time to make Pepita Chocolate Bark.)
6. Step 6Divide half of pudding (about 11/4 cups) among 6 serving glasses. In stand mixer fitted with whisk attachment, mix heavy cream and cinnamon on medium until medium-stiff peaks form, 2 to 3 minutes; fold half into remaining chocolate pudding in bowl until fully incorporated and lightened, then spoon onto chocolate pudding in glasses and dollop with remaining whipped cream.
7. Step 7Break chocolate bark into pieces and place a few on each dessert (you will have bark left over), then sprinkle each glass with a pinch of cayenne.  

Pepita Chocolate Bark

1. Step 1Line baking sheet with parchment paper. In medium bowl, microwave chopped chocolate in 30-second increments, stirring in between, until smooth and melted, 1 minute total. 
2. Step 2Pour melted chocolate onto prepared baking sheet and, using small offset spatula, spread into even 10- by 7-inch rectangle.
3. Step 3Sprinkle pepitas, sesame seeds, and flaky sea salt all over chocolate. Refrigerate until fully set and chocolate snaps when broken, 30 minutes.