Preheat oven to 350. Grease and flour three 8" cake pans then line with circles of parchment paper.

Sift together sugars, flour, cocoa, cinnamon, baking powder, baking soda, and salt in mixer. Add buttermilk, oil, eggs, vanilla, beat on medium speed 2 minutes. Slowly add in boiling water.

Divide evenly among three cake pans. Bake 30-35 minutes, or until inserted toothpick is clean when removed. Cool in pans 10 minutes, flip over, remove parchment paper, and let cool completely on cooling racks.

Melt sugar in large, sturdy saucepan over medium-low heat until completely melted and amber in color. To slowly heat and melt the sugar will take a bit, about 15-20 minutes.

Warm cream and butter in microwave, about 45 seconds.

Quickly stir in butter and heavy cream, being careful as it will bubble up. Stir until all melted and mixed together.

Stir in cinnamon, vanilla extract, and coarse salt.

Pour into heatproof container and refrigerate until completely cool.

When completely cool, pour into mixer. With whisk attachment, whisk caramel until it begins to lighten in color and gain a fluffy consistency. Add powdered sugar and continue whisking until filling is fluffy and creamy.

Melt butter, whisk in cocoa until dissolved.

Alternately add powdered sugar and heavy cream until spreading consistency. Mix in vanilla, vanilla bean seeds, and coarse salt.

Spread half of caramel filling onto first layer of chocolate cake.

Repeat with next two layers of chocolate cake and remaining filling. Top with third layer of chocolate cake.

Frost. Garnish with cinnamon sticks