Preheat oven to 350 degrees. Place pecans on a large baking sheet and lightly toast in oven for 7-8 minutes or until fragrant. When cool, roughly chop and set aside.
In the bowl of a stand mixer, fitted with a whisk attachment, add the cream cheese, sugar and one teaspoon cinnamon. Whip at medium speed until smooth, about 2 minutes. Slowly add the heavy whipping cream and vanilla and continue to whip raising speed to medium-high speed until still peaks begin to form.
Line a 9x5-inch loaf pan with plastic wrap. Make sure enough of the plastic wrap hangs from the sides for easy removal of the cake.
Spread a generous layer of the cinnamon cream cheese whipped cream evenly in the bottom of the loaf pan. Add a layer of the pecans, then the graham crackers. (I used three) You want the whipped cream layer to be as much covered as possible. Continue to layer the whipped cream cheese mixture, the pecans and the graham crackers until you reach the top of the loaf pan. I had 3 layers total. End with a thin layer of the whipped cream cheese.
Cover the cake with plastic wrap and freeze 5 hours or overnight. Remove from the freezer an hour before serving and place in refrigerator to soften a bit. Uncover the loaf pan. Place a serving platter over the cake and invert the cake onto the platter. Peel away the plastic wrap. Dust the top of the cake with ground cinnamon, if desired. Cut into slices and serve immediately.