Preheat oven to 375°F/190°C. Coat a 10-inch (25 cm) loose-bottomed, fluted tart pan with nonstick spray. Place tart pan on a parchment lined half-sheet baking pan and set aside.

For the Crust: Crumble graham crackers directly into a food processor fitted with a metal blade along with the pecans. Pulse on and off, then process until evenly and finely ground. Pulse in cinnamon and melted butter, pulsing on and off until evenly moistened and beginning to clump.

Scrape crust mixture into prepared pan and press very evenly across bottom and along sides. I like to use a flat-bottomed measuring cup or glass to help press the crumbs.

Bake for about 10 minutes or until dry and just beginning to color a light golden brown. Cool on rack.

For the Filling: Place the finely chopped chocolate in a heatproof bowl. Whisk the cream and espresso together in a saucepan and bring to a boil over medium heat, whisking well to dissolve the espresso. Immediately pour over the chocolate and allow to sit for 5 minutes. The heat will melt the chocolate gently off of the heat. After 5 minutes whisk gently until smooth and creamy, then scrape into prepared pan.

Refrigerate until the ganache filling has firmed up, at least 2 hours or overnight. The tart may be refrigerated up to 2 days, in a covered container, such as a cake dome. Unmold tart from pan and dust with a bit of cocoa and/or cinnamon. Serve cold, in thin slices, heeding the low FODMAP serving size recommendations.