Preheat oven to 350°F (175°C).

Spray a rimmed baking sheet with nonstick spray.

In a medium bowl, whisk together egg white, sugar, brown sugar, cinnamon, salt, and cayenne pepper.

Stir in pecan halves and spread in a single layer on the baking sheet, rounded side up.

Bake for about 30 minutes, until just browned and dry.

Cool on the baking sheet, then separate the nuts and remove any excess coating.

Preheat oven to 350°F (175°C).

In a food processor, blend chocolate wafer cookie crumbs, sugar, cinnamon, and salt.

Add melted butter and process until the crumbs are moistened.

Press the crumb mixture into a 9-inch tart pan with a removable bottom, to within 1/8 inch of the top.

Bake for about 20 minutes, until set. Cool on a rack.

In a medium saucepan, bring heavy cream to a simmer.

Remove from heat and add bittersweet or semisweet chocolate and Mexican chocolate.

Whisk until melted and smooth.

Add butter, one piece at a time, whisking until smooth after each addition.

Whisk in vanilla extract, cinnamon, and salt.

Pour the chocolate filling into the prepared tart crust.

Chill for about 15 to 20 minutes, until the filling begins to set.

Arrange the spiced pecans in concentric circles on top of the tart.

Chill for at least 4 hours, until fully set.